Electronics I Study GuideFollow the yellow brick road.To a passing VOCATS score!Bill Sorenson, South Stanly High

X101 Basic Electrical Theory and MagnetismStatic electricity: static electricity is a building of electrical charge (electrons) on an object that is not electrically balanced. Think about dragging your feet on the carpet and then shocking your sibling.Electrical work: Work happens when in an energy system, something causes something else to move or change shape. In electrical systems, electricity is converted to heat, light, sound pressure, etc.Electrical Energy: Energy is the ability to do work. A water tower holds a lot of water with gravity pushing down on it. If you open a drain at the bottom, the energy causes the water to flow, which is work. In electrical systems the energy can be either electrical or magnetic or others.

Two types of energy: POTENTIAL ENERGY and KINETIC ENERGY.POTENTIAL ENERGY is defined as energy at rest, while KINETIC ENERGY is defined as energy at work. Think of it this way: a rock on top of a hill that is at rest, has Potential to do work. Once the rock begins to roll downhill, and is in motion, it is doing work. (Kinetic)Energy LevelsA.S. WSHS

The AtomThe atom has three particles:The proton, inside the nucleus, has a positive chargeThe neutron, inside the nucleus, has NO charge propertiesThe electron, which orbit around the nucleus, are negativeELECTRONS on the outer shell are called Valence electronsThey are the electrons that move to form electrical current.The flow of electrons IS electricity!!!

What is electricity?Current is the flow of electrons from atom to atom. Letter symbol is I, measured in amperesVoltage is the force or pressure that causes flow when a path is available. Letter symbol is E or V, measured in volts.Resistance is the opposition a material offers to that flow. Letter symbol is R, measured in ohms.Conductance is the ability for flow that a material has. Its the opposite of resistance. Letter symbol is G, measured in Siemans

Basic Electrical symbols, unitsVisit the following website to Review basic electronic units

http://www.wisc-online.com/Objects/ViewObject.aspx?ID=ENG902

MagnetismMagnetism is a natural force that causes certain materials to be attracted to others. Magnetic attraction/repulsion is VERY similar to electromechanical attraction/repulsionMagnetic termsPermeability: ability of a magnet to store magnetic forceFlux: the lines of magnetic forcePole: place in a magnet where lines of flux enter or leave the magnetLodestone: a naturally occurring magnetReluctance: Opposition a material offers to being magnetizedFerromagnetic: materials that aid in developing magnetic fields.

Magnetism ContinuedMagnets can be made using Electrical current looped into coils.Placing an iron core in an electromagnet makes it much stronger.Electronic devices utilize magnetism in a lot of different applications.

Lines of force leave the north poleAnd enter the south.

OPPOSITES

LIKEATTRACTREPEL

Magneto motive ForceMagnetic lines of force are created and can be used to actually move things. This is how many electrical motors work. By using electromagnets and fixed magnets, we can produce MECHANICAL energy from electrical. The way this is done varies greatly.

X102 Electrical SafetyRisks of electrical workLasers: Many devices can damage your eyesFire: Excess current flow can cause firesClass A: Combustibles, paper, wood, etcClass B: Liquids, gas, kerosene, etcClass C: Electrical/electronic firesClass D: Burning metals, phosphorus, etc.Shock: electrons moving through the body. Burns, heart stoppage, muscle damage, death.1 amp of current across your chest can be fatal.01 amps you lose muscle control.001 amps you feel a slight tingle

NFPA 70 Natl Fire ProtectionNational Fire and Protection AssociationSets NEC code for all wiring which the states use for state codeSet Fire prevention standards for all types of construction and electrical electronic codes.Local codes may supersede state codes which may supersede NFPA codes, but only to be more stringent

FIRST Aid and Electronics JobsFirst aid for electrical shockRemove Victim from source safely by turning off breaker or switch or using non conductive materialTreat for traumatic shock, elevate legs and keep warmIf needed administer CPR IF TRAINEDTreat burns by keeping them as clean as possibleGET HELP ASAP!

Multimeters: how they workMultimeters are meters designed to measure the big three: Current, Voltage, and ResistanceSee picture belowDigital MeterAnalog MeterVolt, ohm, milliameter

Analog Meters -VOMUse a meter driven by a Darsonval Movement. This uses the magnetic field generated by voltages to move the needleGenerally have to be Zerod to measure ohms. Zero by touching leads together and adjusting ohms.Usually have one or more amperage scales with jacks for each.Meter scale is more difficult to read but can be highly accurateSimpson 260 was the standard VOM for decades.

Digital MetersDigital meters use digital readoutsUsually have jacks for volts/ohms and different amperage levels.Range switch selects range of reading.Function switch selects what you are measuring.Do NOT require zeroing.Measure RESISTANCE and VOLTAGE in parallel and Current in Series.NEVER MEASURE RESISTANCE WITH POWER ON.

Light level, SPL, other metersLight level meter: Measure amount of light present in lumens. Used to find optimal levels for pictures, videos, etc.SPL meter: Measure sound pressure or noise in Dbs. Decibels are levels of sound relative to a specific noise level.EMF or Gauss meter: Meter designed specifically to measure electromagnetic energy in a space.

Capacitors: BABY BATTERIESA capacitor is simply two metal plates separated by some kind of insulator.A capacitor stores a charge on those plates much like a battery.A capacitor charges and discharges MUCH faster than a battery.Capacitors are measured in FARADS, named after Faraday.Capacitors are always measured in tiny units such as microfarads, pico farads.Capacitors do NOT work like resistors mathematically. Capacitors in parallel add up while in series they divide (the 1 over method for resistors)

Capacitors: what they look likeMylarCeramic Disc

Capacitors: What they doCapacitors store a charge.Capacitors can be used to BLOCK low frequencies.Capacitors are often used to manipulate AC waves in radio tuners and such.Capacitors do NOT PASS DC current.Capacitors are used to filter power supplies, they do this by smoothing out voltage.Electrolytic capacitors that look like little cans can explode if hooked up backwards.

Capacitor MathXC = opposition to changing AC in ohms

Capacitor Color CodeUsed for very small caps that utilize a color code instead of digits. VALUES below in Pico farads

Reading Ceramic Disk CapsValues given in Pico farads. Pico farads are Trillionths (1/1,000,000,000,000) of a farad

SCHEMATICS for Capacitors

Resistors: They cause voltage dropsResistors are devices designed to give resistance to manipulate voltages.There are several types of resistors.Resistors give off power in the form of heat.Variable resistors are called potentiometers or rheostats.Letter Symbol for Resistance is R.Resistance is measured in Ohms.

Resistors: What they look like

Series Resistor MathIn series Resistors simply add up.R1 + R2 + R3 = RT Total resistance

Resistors: Parallel MathIn parallel, the total opposition actually goes down so the formulae is:1/R1 + 1/R2 + 1/R3 = 1/RT You can also use the product over sum method for just two resistors.R1 x R2 Divided by R1 + R2

Resistors: The codeMany resistors are so small they use a color code to indicate their value. The code is as follows:First color is first digitSecond color is second digitThird color is multiplier (or number of zeros)Fourth color is tolerance (how accurate it is designed to be) usually 5% or 10%

Resistor color code example

Schematics for Resistors

Electrical InsulatorsInsulators have an atomic structure that OPPOSES the flow of electricity.Common insulators include: Rubber, Plastic, Glass, Ceramic, Paper Insulators generally have 5 or more valence electrons in their outermost orbit.Insulators are used to CONTAIN/DIRECT current.

Electrical ConductorsConductors have an atomic structure that make them allow for current flow easily.Most conductors are metals.Good conductors generally have just one electron in the outermost shell, called the valence shell.Conductors Route Electrical currentThere are literally thousands of different types of conductorsAll conductors have some resistance and the longer the wire, the more resistance.Conductors CAN act as antenna as well so sometimes, they have to be grounded.

Types of Wire used as conductorsConductors can be multi stranded wire or solid core.Conductors can be made of copper, aluminum, or any other metal.Wire is measured by feet or meters for length and by GAUGE for diameter of conductor.The smaller the GAUGE, the BIGGER the wire.#22 wire is small while #4 wire is bigger

American Wire Gauge

Switches

Some examples of switches

Schematics for switches

FUSES: 1 time safety devicesFuses are simply strips of conductive material designed to OPEN a circuit upon over current conditions.FUSES PREVENT FIRES by limiting current to that which the circuit can safely handle.Fuses are rated for voltage and more importantly CURRENT at which it opens.Fast acting fuses are designed to open immediately.Slow Blow fuses are designed to withstand short duration over current events.Thermal fuses blow on HIGH temperature.

Fuses: Pix and schematics

FUSE SAFETY:ALWAYS REMOVE POWER BEFORE REMOVING A FUSE!NEVER REPLACE A FUSE WITH ONE RATED AT A HIGHER CURRENT OR LOWER VOLTAGE!LETHAL VOLTAGES ARE PRESENT ACROSS THE CONNECTIONS OF A BLOWN FUSE!IF A FUSE BLOWS TWICE, LOCATE THE SHORT IN THE CIRCUIT

If the fuse keeps blowing!In a circuit that keeps blowing a fuse, the problem is a short circuit somewhere.You can troubleshoot by placing a resistor in line with the power going to the fuse and then looking for component with zero voltage drop.Always use extreme care when troubleshooting fuses as YOU could make the circuit if you bridge the fuses gap.

Circuit Breaker: Resettable fuseA circuit breaker is designed to trip (OPEN) a circuit when too much current goes through it.Circuit Breakers prevent fires!Circuit Breakers are rated for current and trip current.Some circuit breakers have visual indicators that show when they are tripped.Find the cause of the breaker tripping before resetting.

How a circuit breaker worksAn over current condition causes the electromagnet toPull the catch away from the other contact.

Batteries: We got the POWER!A battery is physically two different metal plates separated by a chemical that causes one metal to give off electrons and the other to attract them.There are hundreds of different types and sizes.Batteries are rated in Voltage available and mAmps/Amps per hour they can deliver.Many batteries pose explosion hazards when shorted or disposed of in fire.The chemicals in many batteries pose health risks so they should NOT be thrown into landfills.

Typical Battery voltagesSLA = Sealed Lead Acid, NiCD = Nickel CadmiumNiMh = Nickel Metal Hybrid, Li-on = Lithium IonLi-polymer = Lithium Polymer

Battery Schematics and PixButton Cell3vSealed Liquid Acid12/24 VDouble AA 1.5 VC battery 1.5V9 V 3.6 V Cell phone battery

Battery Schematics and cellsCells are single battery units while many batteries come in manufactured packs. Example a Car battery has 6 Cells which add up to 12 Volts.

Ohms Law: The STUFF!Ohms law is the relationship between Voltage (V), Current (I), and Resistance (R) Voltage measured in volts is electrical FORCE or pressure. Also called POTENTIAL DifferenceCurrent measured in Amperes is the actual FLOW of Electrons.Resistance is the OPPOSITION to the flow of electrons.

Ohms law, the formulaeFinding CurrentExampleTo find any one of the three,Cover it up and use the other two.

Ohms Law problemProblem #1 A 110 volt wall outlet supplies power to a strobe light with a resistance of 2200 ohms. How much current is flowing through the strobe light?

Choose your answer below0.5 amps2.0 amps 0.05 amps1.0 amps

PROBLEM 2A CD player with a resistance of 40 ohms has a current of 0.1 amps flowing through it. Sketch the circuit diagram and calculate how many volts supply the CD player? Choose your answer below0.0025 volts4.0 volts 10.0 volts 400.0 volts

More Ohms law problems1. A circuit contains two 1.5 volt batteries and a bulb with a resistance of 3 ohms. Calculate the current. ___________2. What is the voltage of a circuit with 15 amps of current and toaster with 8 ohms of resistance? _____________3. A light bulb has a resistance of 4 ohms and a current of 2 A. What is the voltage across the bulb? _________________4. How much voltage would be necessary to generate 10 amps of current in a circuit that has 5 ohms of resistance? ___________5. How many ohms of resistance must be present in a circuit that has 120 volts and a current of 10 amps? _______________6. An alarm clock draws 0.5 A of current when connected to a 120 volt circuit. Calculate its resistance. _____________

UNITS OF POWER!Power is energy convertedIn electronics we measure power in Watts.1 Watt = 1 Volt x 1 Ampere for 1 second.We measure energy USED in Kilowatt-hoursA kilowatt-hour is 1000 watts used over 1 hour.A joule is the SI unit for measuring energy.One kilowatt hour is 3.6mega joules, which is the amount of energy converted if work is done at an average rate of one thousand watts for one hour.

Watts Laws of PowerWatts law demonstrates the relationship between the big three; Current (I), Voltage (V) and Resistance (R) to Power in watts.Power in Watts = Current in Amps x voltsSee the power wheel below for other forms.P = I x ERememberPIE Power!

Power problemsA car stereo draws 10 amps at 12 volts. What is the wattage beingUsed by the system?_______________________If your 220 volt water heater has a 20 amp fuse on the powerSupply, what is the max power possible?_________________

Scientific Calculator in OzA scientific calculator has many functions useful in the study of Electronics:1/X or the reciprocal button for solving Parallel Resistance problems and Series Capacitive problems.Squares button. 2 When you take a number and multiply it by itself, you get the square of it. or square root for finding resonant frequency and in impedance formulae.ENG or EE for scientific notation. Given the inordinately large and small numbers encountered, it is handy to use exponential notation, IE Powers of 10 (more on that later)

Scientific symbols in electronicsSymbols used in electronics study include: Omega, = OHMS, the unit of measure for resistance, reactance, and impedance Lambda, = wavelength, the distance a waveform travels through space, in meters or fractions of Beta, = ratio of collector current to base current in Bipolar Junction Transistor circuits. Delta, means DIFFERENCE or change in. Theta, represents angular displacement in vector diagrams. In phasor graphs for RCL circuits, there is an angular displacement between vectors for XL and XC. Recall Series RCL circuits on the computers.

Using the 1/X for electronicsGiven a parallel resistor circuit, you will need to find the total resistance. If the 3 resistors were 470 , 1500 , and 3300 use the following sequence:470, 1/X + 1500, 1/X + 3300, 1/X =, 1/XThe answer is 322 ohmsNOTE: On graphing calculators the process is:470, X-1 + 1500, X-1 + 3300, X-1 =, X-1 This formula works for Resistors in parallel and capacitors in Series for finding TOTALS.

Problems using the 1/Xhttp://www.wisc-online.com/objects/ViewObject.aspx?ID=DCE8604VISIT the following links for practice using the I/X button in parallel circuits

Square RootsThe square root of a number is the number that multiplied by itself equals that number.Example the square root of 16 is 4 because 4 times 4 equals 16The formula for impedance in Series RCL circuits is Z = R2 + (Xc Xl )2Note the Square root is over the entire series.If R = 47 ohms, XL = 980 ohms, XC = 1200 ohms, find Z using the formulaAnswer is 224 ohms.

More math on RCL circuitsWe use the formulas for XLAnd XC first, which includesUsing the 1/X function.Then we use the impedance Formula which uses square Roots and squares.DO NOT GET BLOWN AWAY BY THE MATH, ITS JUST APPLYINGFORMULAE TO SPECIFIC CIRCUITS.

Scientific NotationIn electronics we use numbers that are so small that they require prefixes to represent them. Micro for example means millionths of or in another words, if you cut something up into a million pieces, one micro would be one piece.We also have to work with numbers so large that they have prefixes too. If you counted the grains of sand on a beach, you would need a prefix to represent trillions of grains.

Engineering NotationEngineering notation is very similar to scientific notation, except that the power of ten can only be a multiple of three and the whole number can be any number from 1-999.Remember: Moving the decimal place to the right makes the exponent move in a negative direction, conversely moving the decimal place to the left makes the exponent move in a positive direction.

A.S. WSHS

Scientific notation prefixes

exaE1000610181000000000000000000QuintillionpetaP1000510151000000000000000QuadrillionteraT1000410121000000000000TrilliongigaG100031091000000000BillionmegaM100021061000000Millionkilok100011031000Thousandhectoh10002/3102100Hundreddecada10001/310110Ten100001001Onedecid10001/31010.1Tenthcentic10002/31020.01Hundredthmillim100011030.001Thousandthmicro100021060.000001Millionthnanon100031090.000000001Billionthpicop1000410120.000000000001Trillionth

MeasurementsCurrent Measurement: Current is the flow of electrons through a circuit.Letter symbol is I (for Ions or atoms with a charge)Unit is AMPERES, often referred to ampsMeter MUST be PART of the circuit for current to be measured.Just like any flow meter, the meter measures what goes through it.

Current measurement diagramThe current inthe circuitwill go thruTHE METER to be measured

Steps to measure CurrentTurn off the circuitSet meter to highest range firstInsure common lead in the black jack.Insure red lead is in the correct amperage jack. There are often two jacks, hi and low.Connect to circuitRestore powerRead meter and adjust range scale.DANGER: DO NOT CONNECT OR DISCONNECT WITH POWER ON

Voltage Measurement Voltage is electrical pressure that pushes electrons.Letter symbol is V (voltage) or E (electromotive force)Unit is VOLTSVoltage is either AC (alternating) or DC (direct)AC is constantly changing direction and sizeDC is consistently in one direction and polarity.VOLTAGE Is MEASURED ACROSS the device.

Measure DC and AC VoltageRemember! You can only test voltage when the circuit is powered If there is no voltage coming in (power supply) then there will be no voltage in the circuit to test! It must be plugged in (even if it doesn't seem to be working) Voltage is always measured between two points There is no way to measure voltage with only one probe, it is like trying to check continuity with only one probe. You must have two probes in the circuit. If you are told to test at a point or read the voltage at this or that location what it really means is that you should put the negative (reference, ground, black) probe at ground (which you must determine by a schematic or somewhere else in the instructions) and the positive (red) probe at the point you would like to measure. If you're getting odd readings, use a reference voltage (even a 9V battery is a reasonable one) to check your voltage readings. Old meter batteries and wonky meters are the bane of your existence but they will eventually strike! Good places to take reference voltages are regulated wall plugs such as those for cell phones. Two meters might also be good :) Voltage is directional If you measure a battery with the red/positive probe on the black/negative contact and the black probe on the positive contact you will read a negative voltage. If you are reading a negative voltage in your circuit and you're nearly positive (ha!) that this cannot be, then make sure you are putting the black probe on the reference voltage (usually ground) DC voltage and AC voltage are very different Make sure you are testing the right kind of voltage. This may require pressing a mode button or changing the dial. Unless otherwise indicated, assume DC voltages Multimeters have different input impedances that affect readings of high impedance circuits For example, measuring a sensor that has 1Mohm impedance with a 1Mohm impedance meter will give you only half the correct reading

Correct Jacks for Voltage Black Lead usually in The Common Jack.

Red Lead usually in theVolts/Ohm Jack.

DMM Voltage Function switchesVolts DC FunctionV with two linesVolts AC FunctionWavy line

DMM Voltage Range selectionFind the RANGE that will be LARGER than the voltage you expect.If unknown voltage is expected, use HIGHEST RANGE!20 V range selectedFor expected values UP TO 20V

Voltage measurement ExamplesMeasuring a 1.5V BatteryMeasuring a plug in power adapter.Note the polarity is indicated on the labelOf the adapter. If you get a negative voltageYou may have the leads backwards.

Measuring adaptersACAC output, use the VoltsAC function

Measuring adapters DC9 Volts DC output Use 20 Volt DC functionNote: an unloaded powerAdaptor usually readsHigher than rated. YouMight see 11 or 12 voltsHere.OBSERVE POLARITY

Measuring RESISTANCE

Measuring ResistanceRemember! You can only test resistance when the device you're testing is not powered. Resistance testing works by poking a little voltage into the circuit and seeing how much current flows, its perfectly safe for any component but if its powered there is already voltage in the circuit, and you will get incorrect readings You can only test a resistor before it has been soldered/inserted into a circuit. If you measure it in the circuit you will also be measuring everything connected to it. In some instances this is OK but I would say that in the vast majority it is not. If you try, you will get incorrect readings and that's worse than no reading at all. You can make sure your meter is working well by having a 'reference resistor' to test against. A 1% 1K or 10K resistor is perfect! Low batteries can make your multimeter inaccurate. Resistance is non-directional, you can switch probes and the reading will be the same. If you have a ranging meter (as most inexpensive ones are), you'll need to keep track of what range you are in. Otherwise, you will get strange readings, like OL or 1., or similar, or you may think you're in K when really you're in M. This is a big problem for beginners so be careful!

Jack it up for ResistanceBlack Lead is in Common

Red Lead is in Volts/Ohm

(Most meters)

Range and Function for Resistance.For most meters, there is a rangeOf resistance functions. Select theRange Above the expected resistance. Ex, to Measure a 470,000 ohm resistor, You Would move the selector to 2 M for 2 million ohms.

For unknown values start at LOWESTRange first as you can damage someComponents with the high ranges.This meter is set to measureUP TO 20k (20,000) Ohms

Example: checking a resistorNote that the range/function switch is set to 20k ohms indicating this is a reading of 9,820. Probably a 10 K ohmresistor

Checking a photo sensor (ohms)This is an example of testing a photodiode with an ohmeter. The photodiode changes resistance based on light. As you change the amount of light available to the component, the resistance value will change. to see a video of this go to: http://www.ladyada.net/learn/multimeter/resistance.html

Continuity IS a resistance checkThe continuity test is a check to see if there is a low resistance path forcurrent to flow. Its useful in checking fuses, lamps, and conductors. Most meters indicate continuity with an audio BEEP so it is sometimesreferred to as a BEEP Check. YOU HEAR A BEEP, YOU HAVE A PATH OF LOW RESISTANCE, IE, CONTINUITY.On many meters the continuity function is the same as the Diode Check. Sincediodes and bipolar transistors have very small resistance values, the meterWill, by default send a very small current through to check.NEVER USE A HIGH RESISTANCE RANGE ON A SEMICONDUCTOR: DiodeOr transistor. You can destroy the device.Meter set to continuity and diode check.This particular meter also checks capacitance.

Measuring PowerSince power is energy converted it is much more complicated to measure than voltage, current, resistance.Mathematically electrical power is voltage times current so it is often calculated versus measured.A wattmeter is a tool designed to measure power. Most techs do NOT carry wattmeters.Kilowatt meters are used to measure power consumed. The unit for power used is often Kwh or Kilowatt hours, discussed earlier.A line monitor/analyzer is a power meter that records voltage and current levels.

WattmetersHand Held WattmeterResidential Kilowatt hour meterThis guy plugs in between your wall and a device and measures the power used.This guy measures the power that goes into your home or business. It does this by measuring current at line voltage.

How to read a watt meterMost newer residential meters use digital displays showing kwhs used. This is based on current measured through the meter and the voltage of the service.On older spinning dial meters: Use a stopwatch (many smart phones have this function built-in) to determine how long it takes the spinning disk in an analog meter to make a single revolution. Now use your Kilowatt factor number in this simple equation: 3600 times your Kilowatt factor divided by the number of seconds for the disk to make one revolution. The number you get is your usage rate in watts. Kwatt factor is listed on the label. Read more: How to Read a Wattmeter | eHow.com http://www.ehow.com/how_6158336_read-wattmeter.html#ixzz1M3XlqZUs NOTE: Some watt meters actually send a reading via radio signal.

Wattmeter test equipmentSpecialized hand held wattmeter used to measure power. Uses special breakout connectors to measure current AND voltage simultaneously. These are NOT commonly used and are expensive tools.

SERIES DC Circuits: 1Path!A series DC circuit has only one path for current to flow.The current flow is the SAME throughout the circuit: IT = IR1 = IR2 = IR3The resistances will add up to a total: RT = R1 + R2 + R3The loss of electrical pressure at each load will add up to total voltage: ET = ER1 + ER2 +ER3

Series ExampleThe electrical current leaves the negative terminal of the battery and flows through R3 and then through R2 and finally R1 before returning to the battery. **** ITS THE SAME CURRENT EVERYWHERE!The total resistance is 1.2k + 3.3 k + 680 = 5180 ohms (RT)(IT) or total current is found using Ohms law; 10 volts divided by 5180 ohms = .00193 or 1.93 mAmpsAnywhere you measure current, it will be the SAME

Series Circuit FormulaeKirchoffs VLaw

Kirchoffs laws for SeriesKirchoffs voltage law states The algebraic sum of the drops around a closed loop equals the applied voltage.This is a fancy way of saying that the voltage applied to the circuit (battery) will equal the voltage drops of the loads added up. ET = E1 + E2 + E3

Series circuit PictorialInstead of resistors, this circuit uses lamps but the math is the same. The SAME current that lights one bulb, lights them all.Challenge Question: If you removed one of the three lamps, would the other two be brighter or dimmer?????ANSWER: BRIGHTER

Short circuit in SeriesA short circuit is an UNWANTED path for current to flow with little or no resistance. In the circuit above, what will happen to the first lamp if the second lamp is shorted out? IT WILL GET Brighter because there is less resistance and voltage is no longer being dropped across the second lamp. SHORTS CAN CAUSE FIRES!!!!!!

Open Circuit Fault in SeriesAnother thing that go wrong is a break in a circuit (Called an Open). If there is a piece of wire that broke, what would happen to the lights? They would go out because there would be NO path for current to flow. An interesting thing that happens is that you could measure your battery voltage across the break in the circuit.OPEN

Series Circuit Resourceshttp://www.wisc-online.com/Objects/ViewObject.aspx?ID=DCE8304For a good interactive activity on Series circuits, visit this link:

Parallel DC CircuitsA parallel DC circuit has 2 or more paths for current to flow.The current flow through each branch adds up to equal the total in the circuit IT = IR1 + IR2 + IR3The resistances will NOT add up to a total: 1/RT = 1/R1 + 1/R2 + 1/R3 (this is called the reciprocal method)Each Branch is connected to both sides of the battery so VOLTAGE IS THE SAME for each load ET = ER1 = ER2 = ER3

Parallel ExampleEvery resistor or lamp is connected directly to the battery. This means that THE BATTERY VOLTAGE IS AVAILABLE TO ALL LOADS and THEY ARE THE SAME VALUE

Adding more branches actually causes resistance to GO DOWN, because there are more paths for electrons to flow!

Parallel PictorialEach light bulb is hooked up to both sides of the battery. This is how your home is wired. You can turn off a light in your living room without turning off the TV. Electrons leave the negative terminal of the battery travel down the line and some of it goes to the first bulb, some goes to the second bulb and whatever is left goes to and through the third bulb. The current returns to the batterys positive terminal. NODENODENodes are places where current can divide into different paths.

Parallel Circuit Analysis (math) The potential drops of each branch equals the potential rise of the sourceThe total current is equal to the sum of the currents in the branches.The inverse of the total resistance of the circuit (also called effective resistance) is equal to the sum of the inverses of the individual resistances. One important thing to notice from this last equation is that the more branches you add to a parallel circuit (the more things you plug in) the lower the total resistance becomes. Remember that as the total resistance decreases, the total current increases. So, the more things you plug in, the more current has to flow through the wiring in the wall. That's why plugging too many things in to one electrical outlet can create a real fire hazard.

Go online and Check it out!For a great interactive lessons about parallel dc circuits visit the following links: http://www.wisc-online.com/Objects/ViewObject.aspx?ID=HVC403http://www.wisc-online.com/Objects/ViewObject.aspx?ID=DCE14705http://www.wisc-online.com/Objects/ViewObject.aspx?ID=DCE14805

Series/Parallel CircuitsMany times a circuit will contain some components in series and some in parallel, these are referred to as series parallel or combination circuits.R2, R3, and R4 are in series with each other!R1 is in Parallel with the other three combined.

Solving the SP circuit step 1Find the equivalent resistance for three resistors in series. (R2+R3+R4) (680 + 4,700 + 1,500) = 6880Use the 1 over formula to solve total. 1/1,000 + 1/6880 = .0011453Find 1/.0011453 to get RTTotal Resistance is 873 ohms

Solving the SP circuit step 2If total resistance is 873 ohms and total voltage is 12volts, just use ohms law to find IT, Total Current.12v/873=.013745 amps.Converts to 13.745 mA.

Are there ANY resistors in series with the batter? In this case no, which means there is no resistor with total current.

Note the resistor R1 IS in parallel with the battery. This means R1 has THE SAME Voltage: 12v across it.

Solving the SP step 3What we know so far: RT = 873IT = .0137 A or 13.7 mAVR1 = 12V cause its in parallelwith the battery. If R1 has 12 volts available and 1000 ohms of resistance, then we can use Ohms law to find the current through it (IR1)12V/1,000 = .012 Amps or 12mA

IR1 = 12mA

Solving the SP step 4What we know so far: RT = 873IT = .013745 A or 13.745 mAVR1 = 12V cause its in parallelwith the battery.IR1 = .012 amps or 12 mA Since we KNOW that 13.745 mA entered the node AND that 10 mA went THRU the 1K resistor, whatever is left MUST have gone thru the other path. 13.745 12 = 1.745mA This means that 1.745 mA went through R2, R3, and R4 (as they are all in the same path).

Solving the SP step 5What we know so far: RT = 873IT = .013745 A or 13.745 mAVR1 = 12V cause its in parallelwith the battery.IR1 = .012 amps or 12 mAIR2, IR3,IR4 are ALL .001745 or 1.745 mA Since we KNOW that 3.7 mA flows through the resistors; R2, R3, and R4, all we have to do is use Ohms law to find the voltage for each. V = I x RVR2 = .003745 x 680VR3 = .003745 x 4,700VR4 = .003745 x 1,500

VR1 = 1.1866VR2 = 8.2015VR3 = 2.6175

CHECK THIS OUT!The three HAVE to add up to 12Volts cause strung together, they are in parallel with R1

Solving the SP step 6What we know so far: RT = 873IT = .013745 A or 13.745 mAVR1 = 12V cause its in parallelwith the battery.IR1 = .012 amps or 12 mAIR2, IR3,IR4 are ALL .001745 AVR1 = 1.1866VR2 = 8.2015VR3 = 2.6175

Finding POWER is the same for every circuit and is actually quite simple. For each component, take Voltage x Current to find the power for that component. For TOTAL power, simply use Total Voltage and Total Current.Examples:PR2 = .001745 Amp x 8.2015 Volts= .0143 watts or 14.3 mWatts

PT = 12v x .013745 A = .1649 Watts or 163.9 mWatts

Series Parallel conclusionSeries parallel circuits contain elements in series and in parallel.The mathematical formula for series circuits will work for all components in seriesThe mathematical formula for parallel circuits will work for all components in parallel.The trick is to simplify the circuit

Get out there and practice!Great interactive labs on Series Parallel can be found at:http://www.wisc-online.com/Objects/ViewObject.aspx?ID=DCE12904Note that there are several good labs that allow you to practice Series Parallel at the same web site. Remember: You may have to redraw them to solve them. The next slide covers redrawing to simplify circuits.

Circuit simplification exampleStep 1: Solve for equivalent resistance of R2 and R3 using 1/xReq (resistance equivalent) = 12 ohms.Step 2: Add Req and R1Step 3 This gives you RT of 20 ohms.NOTE: Start furthest away from battery and work back.

The Wheatstone BridgeIt is used to measure an unknown electrical resistance by balancing two legs of a bridge circuit, one leg of which includes the unknown component. Its operation is similar to the original potentiometer

The Wheatstone continuedTo see a simulation of how the Wheatstone MEASURES resistance Visit the following hyperlink. Vary the R3 variable resistor and see what happens.

http://www.magnet.fsu.edu/education/tutorials/java/wheatstonebridge/index.html

Thevenins theoremIn circuit theory, Thvenin's theorem for linear electrical networks states that any combination of voltage sources, current sources, and resistors with two terminals is electrically equivalent to a single voltage source V and a single series resistor R.This is used to solve circuits with multiple voltage sources or current sources.Follow the pattern on the next slide to see how Thevenins theorem works in a simple circuit.To calculate the equivalent circuit, the resistance and voltage are needed, so two equations are required. These two equations are usually obtained by using the following steps, but any conditions placed on the terminals of the circuit should also work:Calculate the output voltage, VAB, when in open circuit condition (no load resistormeaning infinite resistance). This is VTh. Calculate the output current, IAB, when the output terminals are short circuited (load resistance is 0). RTh equals VTh divided by this IAB.The equivalent circuit is a voltage source with voltage VTh in series with a resistance RTh.Step 2 could also be thought of as:2a. Replace voltage sources with short circuits, and current sources with open circuits.2b. Calculate the resistance between terminals A and B. This is RTh.

Example of Thevenins TheoremOriginal circuitCalculate the equivalent output voltage

ContinuedThe equivalent circuit, simplified

Seems confusing?For an EXCELLENT resource to practice with, visit the following link. You will see animations and practice problems.http://www.wisc-online.com/objects/ViewObject.aspx?ID=DCE5903

The Voltage Divider CircuitMany times we need several voltages from a single source.By placing resistive or reactive loads in series we can take a voltage and break it down into fractions of the original voltage.For simplicity, we will look primarily at a DC voltage divider using resistors.

The Voltage DividerIf we apply 12 VDC to this circuit and have two resistors of equal value, we can get 6 volts across either R1 or R2 or 12 Volts across the two combined. 12 volts gives us essentially three different outputs.This works because of Kirchoffs voltage law which says the drops of each series connected load add up to the total.

Another Voltage DividerThis BASIC Series circuit can also be used as a voltage divider. Using ohms law and Kirchhoff's laws we can pull several different voltages off of one 45 Volt source. Find VR1, VR2, and VR3 to get those voltages.VR1 = IR1 x 5000 (10V)VR2 = IR2 x 10000 (20V)VR3 = IR3 x 7500 (15V)

HINT: Remember inSeries ALL currents ARE the same, so just Use IT.How did you find IT to solve thedivider? Ohms law; 45V / 22.5 K

DIGITAL: Numbers for a digital age!Digital electronics utilizes only 2 distinct states. 1s and 0s represent On or Off AND High or LowAnalog electrical signals have varying levels and can be either constant or constantly changing.Digital electronics IS the world you live in so we need to understand the numbering systems used.

Numbers we are familiar withThe numbering system we are most familiar with is decimal.Decimal is based on 10 digits, starting with 0 and going up to 9As you exceed the decimal number 9, the next number moves to the left and has a place value of tens. As you add digits the numbers value increase by powers of ten

Decimal ExamplesThe number 7 equals 7 unique itemsThe number 17 equals 7 unique items PLUS 10 times 1 moreThe number 177 equals 7 unique items, 7 times ten more, plus 1 times 100 more.This seems awful silly to go over but it is important to recognize how decimal numbers work.Decimal numbers can be indicated by a small 10 in subscript after the numberExample 177 in decimal is actually 17710

Place Values in Decimal

Decimal Math examplesIt is easy math but do the following to help you relate place value in decimal numbers:23 + 11 = ______ how many tens? Ones?120 + 45 = ______ how many hundreds?56 + 45 = ______ What did you do with the carry from the ones place?

Decimal math is easy isnt it?

Binary Math, 1s and 0s ONLYIn binary there are only two digits, 1 and 0Just like 10 is the base or radix of decimal, in binary it is 2 because there are only two digits.Everything digital at its most basic level is using nothing more than a series of 1s and 0s to work. These 1s or 0s are called Bits for binary digits.A series of 8 bits is called a Byte. Notice the lower case b means bit and upper case B means Byte.

Binary place values 2 6 = 64, 2 5 = 32 ,2 4 = 16 ,2 4 = 16 ,2 3 = 8 ,2 2 = 4 ,2 1 = 2 ,2 0 = 1 An easy way to remember is to start at the RIGHT side and write a 1, then as you go LEFT, just keep doubling the number. It doubles because the base is 2.

Example: 1012 = 1 one, zero 2s and one 4 Since we are using Decimals to represent binary place values,just add where the ones are. In this case one 410 + one 110 = 510

WE JUST Converted a binary number to a decimal number!

Practice converting BinaryConvert the following binary numbers to decimal.102 = _____ 101112 = _____10 10002 = _____101111002 = _____10111111112 = ______10

Decimal to Binary conversionGotta go both ways.Draw the binary equivalentchart to the left and find the first number LESS than the number you are converting. Then, moving left to right, subtract the first number smaller than that. If the next digit will fit in, subtract it. If not, place a zero in that place. For every number used put a one and for every number skipped, put a zero.

Binary numbers in reviewBinary numbers are all 1s and 0s.The Radix or base number is 2A binary digit is often called a bit8 bits equals one byteIn the binary numbering system each place value goes up in increments of 2.3 binary digits can represent decimal 0 -7104 binary digits can represent decimal 1-1510

Binary conversions practiceFor some practice converting go the following websitehttp://www.mathebook.net/middleschool/eworkbook/binarytodecimalconversion.pdf

Octal Numbers8Octal means 8 so octal is a base 8 systemOctal uses the same digits we use in decimal numbersOctal includes 0,1,2,3,4,5,6, and 7 for a total of 8 digits per place value.Three binary digits can represent any Octal value.Original Computers were 8 bit devices and that is why there is an octal system.

Octal continued, base 8238 equals three 1s and two 8s2 x 8 = 16 + 3 = 1910Converting binary to octal is easy, just recall there can only be 3 bits and the biggest single digit number is 71012 = 510 = 58 11012 = 1310 13 / 8 equals 1 with 5 remainder so 11012 = 1310 = 158

Octal conversions worksheetsFor practice visit the following link:http://www.mathebook.net/middleschool/eworkbook/octaltodecimalconversion.pdf

Gonna put a HEX on you, Hexadecimal, that isBecause of the inordinately large numbers encountered in electronics and specifically in computer systems, sometimes we need a numbering system with more digits.Imagine a class with 8 students all needing a unique 1 digit number. Binary would not work, there are only 2 digits. OCTAL would work because there are precisely 8. Decimal would also work with 10 digits.Now think about how many cell phones are in the world (over 5 Billion). Each cell phone MUST have a unique electronic identifier. If we used decimal numbers there would have to be 9 digits used to give each a unique number.

Hexadecimal continuedNow imagine how many memory addresses are in a terabyte hard drive. Terabyte means 1,000,000,000,000 bytes. 13 digits in decimalWe need a numbering system that has MORE digits so that fewer digits can be used to make unique identifiers. These numbers are used in Cell phones and computers and are call Hexadecimal. Hex means 6 and decimal means 10 so it is a base 16 numbering system.

The wonder of HexadecimalSince just one hexadecimal digit can represent up to 16 unique things, you need fewer digits to represent larger numbers.Remember the class room example of 8 students? What if the class had 12? Now octal and decimal both do not work, but Hexadecimal would. (up to 16 unique #s)Students 0 thru 9 and three students with letter ids, A, B, and C

The hex code compared to decimalHex uses decimal numbers and the letters A thru F0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, FThe letter symbols are equivalent to our decimal numbersA16 = 10 10 B16 = 11 10 C16 = 12 10 D16 = 13 10 E16 = 14 10 F16 = 1510

Converting hex, the mathHexadecimal place valuesEXAMPLE 12F16THE F means number of 1sThe 2 is number of 16s (the base)The 1 is number of 162 or 256sTherefore: (1 x 256) + (2 x 16) + (15 x 1) = 30310REMEMBER the letter F16 is the same as 15 in decimal.12F16 = 30310

Man, theres gotta be an easier way!Method 1: Divide by 16 and list remainders. See the following for demonstration: http://www.wisc-online.com/ListObjects.aspx

Method 2: Each Hex digit represents 4 binary bits. Convert each into the binary equivalent, combine the binary numbers and convert to decimal.Example: F416 F16 = 11112 and 416 = 01002Combined they give you 111101002111101002 = 24410Remember to convert binary to decimal start at the farthest right digit, write a 1 above it and going left, just double it each time. Where ever there is a 1, simply add the decimal equivalent

The numbering systems together

DecimalBinaryOctalHexadecimalBase-10Base-2Base-8Base-16000011112102231133410044510155611066711177810001089100111910101012A11101113B12110014C13110115D14111016E15111117F161000020101710001211118100102212191001123132010100241421101012515221011026162310111271724110003018251100131192611010321A2711011331B2811100341C2911101351D3011110361E3111111371F321000004020

Binary Coded DecimalIn computing and electronic systems, binary-coded decimal (BCD) is a digital encoding method for decimal numbers in which each digit is represented by its own binary sequence. In BCD, a numeral is usually represented by four bits which, in general, represent the decimal range 0 through 9.

BCD to Decimal and backExample of a decimal number displayed in BCD: 9110Decimal: 9110 UNCOMPRESSED BCDBinary : 0000 1001/ 0000 000191= 9110Now in Compressed BCD 9110 9 11001 0001

MORE BCDAs you can see, the highest number that BCD can represent is 910Since many devices use BCD, knowing how to handle this system is important. You must realize that BCD and binary are not the same. For example, 4910 in binary is 1100012, but 4910 in BCD is 01001001BCD. Each decimal digit is converted to its binary equivalent. 4 BITS per BCD number

NOTE the SUBSCRIPT BCD to represent the number system

There is a house in New Booleans?Boolean algebra is the algebra of two values. These are usually taken to be 0 and 1, although false and true, etc. are also in common useIn digital circuits, there are 1s and 0s that represent statements of true or false.Example: It is time to go eat: but to make the statement true, there would be two decisionsIt has been several hours since you ateYou are hungry

Decisions, decisions, decisionsIt is time to go eat: but to make the statement true, there would be two requirementsIt has been several hours since you ateYou are hungryWe can express that statement by saying it is time to eat BECAUSE A: It has been several hours since you last ate AND B: You are hungry

Logic (decision Gates)We can express that with this AND gate. An AND gate needs all the inputs to be true (high) for the output to be trueY means output orYES Its time to EAT!A 1 here means A is trueA 1 or high here, means B is true

Logic (And Gates)It is time to go eat: but to make the statement true, there would be two decisionsA: It has been several hours since you ateB: You are hungryY means output orYES Its time to EAT!A 1 here means A is trueA 1 or high here, means B is trueWe can express that as a math formula as AB which means A AND B have to be true for the output to be true. Its a little confusing because in the math we are used to AB would mean A times B but in Boolean, it means A AND B.

The AND gate: Looks like a bulletIt is time to go eat: but to make the statement true, there would be two decisionsA: It has been several hours since you ateB: You are hungryY means output orYES Its time to EAT!We can express that as a math formula as AB. We can also use a chart to show the relationship, called a TRUTH TABLE Only high output

INPUTOUTPUTABA AND B000010100111

The Logic gate: OrAnother decision or logic gate is the OR gate.The OR gate only has a high output when one or more inputs are true, but NOT necessarily all.Example: I need to go to sleep is the gateI havent slept in two daysThe doctor just gave me a sleeping pill

The Or gate (looks like an arrow)I need to go to sleep!I havent slept in two daysThe doc just gave me a sleeping pillIn this instance, I need to go to sleep if EITHER input statement is true. If I have not slept in two days OR the doctor just gave me a sleeping pill IT IS TRUE. This is called an OR gate and the Boolean representation would be A + B. Again, this is a little confusing because in our math that would mean A plus B, but in Boolean logic it means OR.High output for ANY high input or both

INPUTOUTPUTABA OR B000011101111

Exclusive Or Gate?For some decisions we have either/or but not BOTH situations.The gate that makes this logical decision is called an Exclusive OR Gate.The output is high when one or the other but NOT both inputs are high. The following page is an example of an exclusive OR decision, the Boolean math expression and the truth table

XOR or exclusive orThe output statement is May has a date Friday night.The input statements would be:She has a date with John at 9 PMShe has a date with Jerry at 9 PMObviously, May can have a date with one but not both or May could not have a date at all.On the next slide you will see the XOR symbol, Boolean expression, and truth table

XOR, one or the other, not bothGoing with JohnGoing with JerryMay has a date!Lets hope may either has a date with John or Jerry and not both, ;).Boolean expression: The circle around the OR sign (+) means exclusive. One or the other, but NOT bothA or B, but NOT Both

INPUTOUTPUTABA XOR B000011101110

Inverters aka NOT GATEBecause digital systems have a high and a low representing 1 or 0, sometimes you need to flip a signal.A gate that specifically inverts an input is called an inverter or Not Gate.The truth table is too simple: High in, Low out. Low in, High out.The Bar above the A meansInvert it. You would say this as A NOT

The Not gate as part of anotherThe inverter gate is sometimes actually part of an AND Gate or an OR Gate.We say that an AND gate with a built in inverter is a NOT AND or NAND GATE.We say that an OR gate with a built in inverter is a NOT OR or NOR Gate.NAND: NOT ANDNOR: NOT OR

The NOT AND, NAND GATEBoolean expression: This means NOT (A and B)One way to solve the NAND is to just go with the and gate logic and flip over the output. Opposite Of And!

INPUTOUTPUTABA NAND B001011101110

The NOT OR, NOR GATEThe Boolean expression is:Which means NOT( A or B)Just like the other not gate, you can solve this by seeing what would be there if it were an OR gate and just flip the output.Opposite ofAn OR gate

INPUTOUTPUTABA NOR B001010100110

Schematics and Block diagramsTo simplify drawings that show the connections and components in a circuit, schematic diagrams use standardized symbols for components.Schematic diagramfor 10 Volt reference circuit. The symbols represent components

Common Schematic Symbols

Schematic Diagram continuedSchematic Diagram for a flashlight

Block DiagramA block diagram is used for troubleshooting purposes and does NOT show individual components. Rather, it shows the functional units of a device. The input usually enters at the left and top, and ground connections are usually at the bottom.A technician can look for signals at the output side of a block and if they are there, the problem is after that module.Example below: Say a technician does not GET an IF signal to demodulator. He can assume his fault is before that block.Some times block diagrams will show test points between modules

Schematic Versus BlockShows components and connectionsShows functional units

Block to schematic!A technician would use the block diagram to find out where the signal needed is no longer present and then using the schematic investigate specific components and signal paths.The more complex a piece of equipment the more functional modules it will have.Another Block diagram is shown below. (LCD Display)

Test Points! Not Extra Credit!In the schematic above, Test Points (TPs) are provided to make sure the signal/voltage/etc is present. If the signal at TP3 is good, but the signal at TP4 is missing, the problem must be in the devices between the two.Tech pubs often list what should be found at specific TPs either as voltages, or with diagrams for waveforms

Using Test points to BRACKETA good troubleshooting technique is to bracket faults.For a system that is not working, test the TP in the very middle of the diagram.Inputs usually come in from right, VCC from top and ground from bottom.If the signal is good at the TP in the middle, pick a point half way between there and the output.Check there. This allows to cut the circuit into pieces to make locating a fault quicker

Flow charts, go with the flow yo!Another troubleshooting aid is called a flow chart.

Flow chart symbols

Just for fun flowchart

Logic Probes and pulsersTo troubleshoot digital circuits sometimes you need a simple device to locate high and low voltage levels.A logic probe is exactly that. It uses circuit power to locate highs and lows.A logic pulser on the other hand, actually INJECTS a signal into digital circuit.By chasing highs and lows, you can find the faulty component.

Probes and pulsers cautions!The probe can short out a component, be very careful.Injecting a pulse in certain ICs can damage them. Make sure you put the pulses where you need to.CMOS ICs are VERY sensitive to ESD (electrostatic discharge) ESD precautions must be taken when working with them.Probes and pulsers are LOW voltage, digital devices ONLY

Logic Probe in detailUse circuit powerIndicates Hi or LowTTL or CMOS

Logic Pulser in detailPulse per second switchUses Circuit powerExternal Trigger input

More about ESDElectrostatic Discharge (ESD) is the discharge of STATIC charges from one body to another.ESD can destroy/damage IC chips, most computer circuit boards, memory modules, and CPUs.CMOS ICs are particularly vulnerable to ESD.Opening a plastic bag or walking across a room can build a charge of several thousand volts on your bodyYOU WILL RARELY SEE the ESD doing the damage

ESD procedures.Antistat wrist straps are worn on the wrist and conduct a bodys static charge to the GROUND.Antistat wrist straps contain a resistor for safety, just in case you come in contact with current.NEVER wear an antistat wrist strap when working on CRT type monitors.ESD mats are work surfaces that take the charge to ground

ESD Control DevicesAnti stat Bags: ESD sensitive devices are kept in these bags which have conductive layers on the outside. This keeps the charge outside the bag and away from the device.

Antistat Wrist Strap

Anti Stat Mats for workstationsAlligator to Grnd

Computer TechnologyComputers use several different layers of code to operate.At the most basic form, its all ones and zeros.Machine language is code that is specifically written to operate processProgramming languages are designed to perform functions together based on syntax. (syntax is like format)

ASCII Code. Bits to symbolsASCII stands for American Standard Code for Information Interchange. Computers can only understand numbers, so an ASCII code is the numerical representation of a character such as 'a' or '@' or an action of some sort. 8 bits together make a byte and one byte can represent up to 255 different symbols in ASCIIWhen you push an L on a keyboard, the computer uses ASCII Code to understand it.

Sample ASCII table (there are different versions now.

ASCII ExerciseConvert the binary words below to decimal numbers first, then using the code on the next page, decimal to words. Solve the captionIn Decimal: ____ ____ ___ ___ ___ ___ ____

ASCII exercise continued.Now convert the decimal numbers into ASCII symbols (Letters)

Digital Devices beyond gatesWe learned about gates before and banging ones and zeros.We can use gates to store bits and move bits with registers and counters.Registers store data in the form of bits.Counters use bit patterns to perform mathematical function.Remember computers do NOT really use decimal, so many counters work in other radices (numbering systems)

Flip flops are not just for the beachOne device used to make registers and counters is called a flip flopA flip flop can be described as a bit bucket. One flip flop holds one bit.We can move bits into and out of flip flops as data or connect flip flops together to make circuits that count.Hooked up to digital clocks (pulses), Flip flops can do all kinds of neat things like hold data and even count bits.

Flip Flops, symbols, types.An RS Flip flop is made of two NOR gates wired together. R stands for Reset and S stand for Set. Also called an RS LATCH because of the output pattern holding or latching based on inputs.Schematic for an RS Flip Flop. Notice the outputs are Q and QNOT. (opposites)

SR latch operationSRAction00No Change01Q = 010Q = 111Restricted combination

More Flip Flops, the JKThe JK flip-flop augments the behavior of the SR flip-flop (J=Set, K=Reset) by interpreting the S = R = 1 condition as a "flip" or toggle command. Specifically, the combination J = 1, K = 0 is a command to set the flip-flop; the combination J = 0, K = 1 is a command to reset the flip-flop; and the combination J = K = 1 is a command to toggle the flip-flop, i.e., change its output to the logical complement of its current value.

More on the JK (universal FF)

JK Flip Flop operationCharacteristic tableExcitation tableJKQnextCommentQQnextJKComment00Qhold state000XNo change010reset011XSet101set10X1Reset11Qtoggle11X0No change

The D Flip flop, for delayThe D ip-op is the most common flip-flop in use today. It is better known as data or delay flip-flop (as its output Q looks like a delay of input D)The Q output takes on the state of the D input at the moment of a positive edge at the clock pin (or negative edge if the clock input is active low). It is called the D flip-flop for this reason, since the output takes the value of the D input or data input, and delays it by one clock cycle. The D flip-flop can be interpreted as a primitive memory cell, zero-order hold, or delay line. Whenever the clock pulses, the value of Qnext is D and Qprev otherwise.

InputsOutputsSRD>QQ'01XX0110XX1011XX11

Digital Timing Flip flops and other digital devices have basically two timing signals.Clocks are pulses from another circuit which help to push through data and perform the processes.Data itself has timing. On this level, data is essentially good ole ones and zeroes.

You got the Time Mr.?Setup time is the minimum amount of time the data signal should be held steady before the clock event so that the data are reliably sampled by the clock. This applies to synchronous circuits such as the flip-flop.Hold time is the minimum amount of time the data signal should be held steady after the clock event so that the data are reliably sampled. This applies to synchronous circuits such as the flip-flop.To summarize: Setup time -> Clock flank -> Hold time.

Output! (hi)Time is on my side, yes it is!Tsu = SET UP TIMETh = HOLD TIMETco = Propagation delay (Time from clock to output) Essentially, how fast the flip flop changes state.

Digital CountersIn digital logic and computing, a counter is a device which stores (and sometimes displays) the number of times a particular event or process has occurred, often in relationship to a clock signal.

Count em up in binary fellas!In electronics, counters can be implemented quite easily using register-type circuits such as the flip-flop, and a wide variety of classifications exist:Asynchronous (ripple) counter changing state bits are used as clocks to subsequent state flip-flopsSynchronous counter all state bits change under control of a single clockDecade counter counts through ten states per stageUp/down counter counts both up and down, under command of a control inputRing counter formed by a shift register with feedback connection in a ringJohnson counter a twisted ring counterCascaded counter- counters input other counters

Ripple Counter (asynchronous)An asynchronous (ripple) counter is a single K-type flip-flop, with its J (data) input fed from its own inverted output. This circuit can store one bit, and hence can count from zero to one before it overflows!

More Ripple please!This counter will increment once for every clock cycle and takes two clock cycles to overflow, so every cycle it will alternate between a transition from 0 to 1 and a transition from 1 to 0.

More Ripple please!This creates a new clock with a 50% duty cycle at exactly half the frequency of the input clock. If this output is then used as the clock signal for a similarly arranged D flip-flop (remembering to invert the output to the input), you will get another 1 bit counter that counts half as fast. Putting them together yields a two-bit count

Ripple counter pix, dataCycle of clock pulses2 JK Flip flops combined to make a RIPPLE counter. Counts to a decimal 3 then resets to zero. Recall two bits can add up to 3 in decimal112 = 310

CycleQ1Q0(Q1:Q0)dec0000101121023113

Synchronous CountersA simple way of implementing the logic for each bit of an ascending counter is for each bit to toggle when all of the less significant bits are at a logic high state. For example, bit 1 toggles when bit 0 is logic high; bit 2 toggles when both bit 1 and bit 0 are logic high; bit 3 toggles when bit 2, bit 1 and bit 0 are all high; and so on.See the next slide for more!

Synchronous counter 4 BitsOutput is BINARY, this display converted it for usA lot of times the output will be 4 LEDs representing 4 binary bits!

Decade Counter: Decade is 10 YearsA decade counter is one that counts in decimal digits, rather than binary. A decade counter may have each digit binary encoded (that is, it may count in binary-coded decimal, as the 7490 integrated circuit did) or other binary encodings (such as the bi-quinary encoding of the 7490 integrated circuit). Alternatively, it may have a "fully decoded" or one-hot output code in which each output goes high in turn (the 4017 is such a circuit).

Decade Counter in actionDecade Counter feeding 10 LEDs to count up to 1010. We could also have different output displays such as 7 Segment LEDs to show the DECIMAL OUTPUT OF THE CIRCUIT. The Johnson 4017 Chip is commonly used for these applications.

Ring CountersA ring counter is a type of counter composed of a circular shift register. The output of the last shift register is fed to the input of the first register.Bottom line is that output of the counter goes back into the input in a RING pattern.

Two types of Ring CountersA straight ring counter or Overbeck counter connects the output of the last shift register to the first shift register input and circulates a single one (or zero) bit around the ring. For example, in a 4-register one-hot counter, with initial register values of 1000, the repeating pattern is: 1000, 0100, 0010, 0001, 1000... . Note that one of the registers must be pre-loaded with a 1 (or 0) in order to operate properly.

Two types of Ring CountersA twisted ring counter (also called Johnson counter or Moebius counter) connects the complement of the output of the last shift register to its input and circulates a stream of ones followed by zeros around the ring. For example, in a 4-register counter, with initial register values of 0000, the repeating pattern is: 0000, 1000, 1100, 1110, 1111, 0111, 0011, 0001, 0000... Compliment means binary opposite.

Ring Counter Outputs

Straight ring/Overbeck counterTwisted ring/Johnson counterStateQ0Q1Q2Q3StateQ0Q1Q2Q3010000000010100110002001021100300013111001000411111010050111200106001130001700010100000000

Cascading counters!If you have ever seen one of those scrolling led signs, you are looking at a circuit driven by cascading countersThe basic concept is one counter feeds into the next which pushes the counts through.By varying types of counters, all kinds of possibilities are created.

Oscillators dont go upstairs?An oscillator is a circuit that oscillates or swings back and forth as an outputThey produce sine waves and other AC waveforms such as square wavesUsed to transmit energy through a media.SINE WAVESQUARE WAVE

Types of OscillatorsThe harmonic, or linear, oscillator produces a sinusoidal output (sine wave)A relaxation oscillator produces a non-sinusoidal output, such as a square, sawtooth or triangle wave. It contains an energy-storing element (a capacitor) and a nonlinear trigger circuit (a latch, Schmitt trigger, or negative resistance element) that periodically charges and discharges the energy stored in the storage element thus causing abrupt changes in the output waveform.There are several oscillator circuits introduced in Electronics II

Multivibrators???? Yea, so what?A multivibrator is an electronic circuit used to drive a variety of simple two-state systems such as oscillators, timers and flip-flops. It is characterized by two amplifying devices, cross-coupled by resistors or capacitors. The name "multivibrator" was initially applied to the free-running oscillator version of the circuit because its output waveform was rich in harmonics.

Three Types of Multivibrators.astable, in which the circuit is not stable in either state it continually switches from one state to the other. It does not require an input such as a clock pulse. Free RunningOutput wave continues until power is removed.

Square Wave Output

Three Types: mono means 1monostable, in which one of the states is stable, but the other state is unstable (transient). A trigger causes the circuit to enter the unstable state. After entering the unstable state, the circuit will return to the stable state after a set time. This circuit is also known as a one shot.Puts out simple one pulse or waveform.Sometimes called a debounce because the signal is sharp edged as opposed to a ramping bounce of energy

1 Shot means 1 output. Notice how SHARP the edges are. These are often used to send one time signals that require sharp edges, such as TRIGGERS.

Three Types: Bi means 2Bi-stable, in which the circuit is stable in either state. The circuit can be flipped from one state to the other by an external event or trigger.It can put out a high or a low, depending on the trigger and hook up.

Bi-stable is often referred to as a flip flopbecause it acts just like one. Hi and Lo out but only when triggered. Output is either a high or a low based on input.

MicroprocessorsMicroprocessor is a term used to described the central processor for computers and other smart devices.Micro means tiny and processor means it performs processes (does math)Micro processors we will look at primarily are computer microprocessors.

Microprocessors, the gutsALU- Arithmetic Logic Unit: Does the lions share of work, as in mathControl Unit: Executes low level commands to move data, and utilize ALUTypical commands: FETCH, DECODE, EXECUTERegisters: Registers are data storage units. Cache: newer processors have special memory just for math it performs over and over again.

Microprocessor Parts PicThis diagram includes RAM and ROM as well as I/O (Input/Output) ports. These are NOT part of the processor but work for the CPU

Examples of ProcessorsActual AMD Processor packageACTUAL CPUThe actual CPU is much smaller

Computer CPU chipsPGA processor. PIN GRID ARRAY. These go into a Zero Insertion Force Socket on the Main Printed Circuit Board (Motherboard) The socket will only accept the chip one way and NOTE the PIN 1 notch PIN 1, notch

LGA Processor ChipsLGA chips dont have pins, they have little conductive bumps. The socket does not have holes for pins, but rather little conductive tabs. Most all new CPUs use this formate because the lack of pins makes them easier to install.PIN 1 Notch LGA CPU

Moving Data inside a PCBuses are paths for data to flow in a computer. There are buses for data and buses for addresses and buses for input and output operations.The diagram shows the basic bus system for a modern computer. Northbridge and South Bridge are chipsets that support the CPU.

The Computer: motherboardThe main circuit board is called a motherboardThe CPU, RAM Memory (thinking memory), and Basic Input Output System (BIOS) live on the motherboard.Hard drives, optical drives, and other devices connect to the motherboard.The motherboard must MATCH the CPU, Memory, and power supply

Example Motherbaord

Computer memory: RAMA CPU needs memory to work with AS it processes. It is called RANDOM ACCESS MEMORY or RAMThe more RAM a CPU has to work with, the faster it can process.RAM is measured in Megabytes and more recently Gigabytes.RAM is also rated at BUS SPEED or how fast it can read write, usually MHz

RAM CHIPSDesktop DIMM (dual Inline Memory Module)Laptop SODIMM, Single Offset Dual Inline Memory Module

Data Storage: Hard drivesThe CPU needs a place to store data as well when not in use.Hard drives and CD ROM, DVD ROM, etc can store data to be accessed as needed.Hard drives are rated in Gigabytes, and now Terabytes of storage.Access time is how long it takes a drive to get dataHard drives also have cache memory.

Hard Drives continuedTraditional hard drives have aluminum platters with microscopic spots that can hold a magnetic charge.A magnetic read/write head floats above writing or reading magnetic ones and zerosSSD are Solid State Device Drives, use flash memory for storage and have NO moving parts. SSD are replacing magnetic drives

Two Types of drivesTraditional Magnetic DriveSSD Drive: NO MOVING PARTS

The Other kind of MemoryEach time you power down a PC its like it dies. The CPU stops thinking, the RAM is emptied, and the Hard Drive ParksSomething has to tell the operating program (system) what hardware is there when the PC is started up.There is a memory chip and battery called BIOS, Basic Input Output System.Its usually a CMOS chip so BIOS and CMOS are often referred to as the same thing.

ROM, PROM, EEPROM, This memory is NOT designed to be used to think, just to remember.Originally it was implemented with ROM Chips (READ ONLY MEMORY)There are also PROM Chips (Programmable READ ONLY MEMORY) which can be programmed a few times.Next comes EEPROM (Electrically Erasable Programmable READ ONLY MEMORY)EPROM is also called FLASH memorySometimes its called EAPROM (alterable)

CMOS Wake UP CallThese types of memory NEEDS power to save the data on them for startup.This is usually provided by a CMOS battery, typically a 3V button cell.CMOS BATTERYCMOS JUMPER

Computer Power SupplyWall voltage is 120 Volts/60 HzThe computer needs extremely accurate and reliable DC voltages to operateTypical Voltages are 5VDC, -5VDC, 12VDC, -12VDC, 3.3VDC and ground.The POWER SUPPLY provides these voltages and the type must match the Motherboard.Power supplies also must deliver enough WATTS to support all the devices

Computer Power suppliesTypical Power Supply ConnectionsComputer Power SupplyWith Light effects

Optical DrivesOptical drives are CD (compact disk) drives and DVD (digital video disk) drives.They use tiny little dips on tracks around the disc to bounce light from an LED off of.If there is a dip, its called a PIT and if not, its called a LAND.These are translated into ones and zeros.

CD and DVD CapacitiesCD: 194 MB (8 cm) 650900 MB (12 cm)DVD: 4.7 GB (single-sided, single-layer common) 8.58.7 GB (single-sided, double-layer) 9.4 GB (double-sided, single-layer) 17.08 GB (double-sided, double-layer rare)

Blue Ray, the new kid on the blockBlue Ray is a new high definition high resolution DVD type format. Blue Ray is currently used exclusively for VIDEO.Blue Ray utilizes enhanced formatting features.Capacities.25 GB (single-layer) 50 GB (dual-layer)

Expansion CardsComputers come with slots for adding devices that were not originally part of the computer.Video cards, modems, network cards and other devices can be added via expansion slots.The slots are identified by the BUS (type of connectors used)Different busses have different abilities.

Expansion Card SlotsAGP SLOTGRAPHICSONLY

Expansion CardsSATA controller Card, For adding SATA DrivesAGP (Advanced Graphics Processor) Slot Video CardThere are many various cards you can use to add wireless, network, Firewire, etc Functions to a computer

On the Case, holding it all togetherCases come in different FORM FACTORS which means shapes and sizes. The Motherboard form factor must match the CASE. NOTE: This CASE IS WATER COOLED!

Computer peripheralsPeripherals means stuff that hooks up to the PC.

Languages, up the chain

Programming continuedAs data and control information moves up the ladder of languages, you reach programming levels.Programs are groups of instructions/commands/etc that cause the processor to perform specific functions.Programs should not be confused with operating systems. An operating system is the PROGRAM to interface a user and hardware.

PLCs ContinuedNewer PLCs are incorporating computers to control and program.

Other smart Devices, PLCsComputers are not the only smart devices.In manufacturing settings there are smart devices to operate equipment.They are called Programmable Logic Controllers (PLCS)They are programmed one step at a time to make a machine perform certain functions.The run on digital commands but OFTEN operate Analog AC and DC equipment.

*****************************************************************************************************************************************************************************************