ELECTRIC CHARGES AND

CURRENT

WHAT IS THE DIFFERENCE?

Static Electricity and Electrical Current is made of the same thing, electrons.

However, in static electricity there is a build up of electrons on an object or area; while electrical current is the flow of electrons in a specific direction.

ELECTRIC CURRENT

Electrical devices need a steady flow of electricity. The steady flow of charged particles is called electrical current. The flow continues until the energy source is used up, or disconnected. However, It can only flow if there is a path to travel through. Electrical Current is measured in Amperes

CONDUCTORS Allow the easy flow of electricity, loosely bound electrons that are free to move from atom to atom

metals like aluminum, gold, copper and silver are examples of good conductors.

INSULATORS Insulators – resists the flow of electrons making the object safe to handleplastic, rubber, glassKeep charges away from body

RESISTORS Resistors-allow electrons to flow but slow them down considerably. This allows the current to slow down.

electron movement in an insulator

electron movement in a conductor

LG: to understand the basics of current electricity

CURRENT ELECTRICITY: THE CONTROLLED FLOW OF ELECTRONS THROUGH A CONDUCTOR

VOLTAGE Voltage – causes current to flow through an electrical circuit

Volt – unit of measure to measure this potential

A Voltage Source (battery or generator) is required to maintain the electrical potential in a circuit.

ELECTRICAL RESISTANCE the opposition to the flow of electricity –

measured in Ohms – symbol is the Greek letter Omega –

Electricity will take the path of least resistanceEx: Lightning Rod

The greater the resistance, the less current there is for a given voltage.a. Longer wires have greater resistance than short wires

b. Thin wires have more resistance than thick wirec. High conductors have less resistance than insulators

SUPERCONDUCTORS

There are some materials that have practically no resistance at extremely low temperatures. These are called Superconductors. Superconductors have many uses including use in power lines to increase efficiency as well as in computers to improve speed.

GROUNDING

As discussed charges/electricity likes to move through lines with lower resistance. Because of this we have developed a procedure known as grounding. Grounding means providing a harmless, low-resistance path-a ground- for electricity to flow. This is used to protect buildings from damage from lightning strikes.

A “Lighting Rod” moves lighting strikes into the ground where the charge is absorbed.

OHMS LAW

Ohm’s Law explains the relationship between voltage (V or E), current (I) and resistance (R) Used by electricians, automotive technicians, stereo installers

It is the push or pressure behind current flow through a circuit, and is measured in (V) volts. 

Current refers to the quantity/volume of electrical flow. Measured in Amps (A)

 Resistance to the flow of the current. Measured in Ohms

1.  Assuming the resistance does not change:As voltage increases, current increases.as voltage decreases, current decreases.

2.  Assuming the voltage does not change: As resistance increases, current decreases. As resistance decreases, current increases.

READ SECTION 6.1

Read section 6.1 in the yellow textbooks and take notes. Title these notes “Circuits”.

Topics for your notes need to include:Defining CircuitsList parts of a circuit and what they do.Open vs. Closed CircuitsShort CircuitsGroundingSafety devicesFusesOther safety devices.

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