voltage in electrical systems. unit 4 voltage pages 71-76 voltage source conductors control...
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Voltage in Electrical Systems
Unit 4 Voltage Pages 71-76 Voltage source Conductors Control element Electrical appliance Electrical loads Electrical circuit Direct current Alternating current Volts
Primary cells Secondary cells
Electrode Cathode
Anode In series Electron
Frequency Voltmeter
Unit 4 Voltage Pages 77
Answer # 1-8
Electrical Systems
Made up of voltage sources, conductors, control elements, and appliances and machines
Batteries/generators, wire/circuits, switches, lights/appliance
Conductor
Any material that allows the movement of
electrical energy through it
Control Element
Wall switch Volume on a radio Variable speed switch
Electrical Load
Motor Light Bulb Appliance
Electrical Circuit
Closed path made by connecting voltage sources, control elements, and electrical loads
AC vs. DC Electricity
AC – Alternating Current
DC – Direct Current
AC Electric charges move
back and forth many times a second in the wire
DC
Electric charges in wires always move in one direction
AC Produced by alternators
DC
Produced by batteries
Dry-cell batteries A chemical produces the voltage
Wet-cell batteries
Contain a liquid electrolyte Usually a strong acid Used to start engines because they
can deliver a lot of power
Primary cells
Not easily recharged
Secondary cells
Easily recharged
The ability to recharge a battery allows us to group these chemical
producers of voltage into two classes
How are DC Voltage sources connected?
The output of a voltage source comes from two terminals called electrodes
DC sources normally have two electrodes
A Positive and a negative
How are DC Voltage sources connected?
Electrons move in the circuit as if they were flowing out of the negative electrode and into the positive
The negative electrode is called the “cathode”
The positive electrode is called the “anode”
How do we produce higher voltage?
DC voltage sources can be added together in series
Positive source must be connected to the negative terminal of the other source in succession
If connected in an opposing manner it will sometimes cause battery damage
What makes up a simple DC Circuit?
How do we make schematics? Symbols:
Battery
Light bulb
Switch
Conductors
AC Voltage
AC Voltage changes direction about 60 times each second
This rate of change is called the frequency
Frequency is measured in cycles per second or hertz
How do we measure voltage
Modern electronics have made digital voltmeters available
Oscilloscopes are used often in analyzing, testing, and troubleshooting electrical systems and circuits
They can also be used as voltmeters
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