# P5, Electric circuits

OCR GCSE Physics P5, electric circuits overview. 21st century spec, can also be used for additional science.

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Physics GCSE
P5: Electric Circuits

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A: Static electricity

Static electricity

Electric charge

Electric fields

Electric current

B: Simple circuits

Electric circuits

Electron flow

Convectional current

C: Electric current

Ammeters

Amperes or amps (A)

Series circuits

Parallel circuits

D: Controlling current

Voltage

Potential difference

Resistance

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Resistors

Ohm's law

Variable resistors

Light-dependent resistors (LDR)

Thermistors

E: Potential difference

F: Electrical power

Power

Work done

G: Domestic appliances

Efficiency

Fuses

H: An electricity supply

Batteries

Generators

Electromagnetic induction

Alternating current (a.c.)

Direct current (d.c.)

I: Distributing electricity

Transformers

The National Grid

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A: Static electricity
Static electricity is an electric charge that has built up on an object.

Plastic can become charged by rubbing it against an object.

Two charges the same repel.

Two different forces attract.

Electric charge is the overall charge that occurs when electrons are added or lost.

There…

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B: Simple circuits
Electric circuits are closed loops of conductors connected to a battery or power

supply.

Circuits need to be complete for them to work.

Effects of the circuit, for example turning on a bulb, are immediate because there is

current in the components all the time.

Charges are…

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C: Electric current
Ammeters are used to measure the electrical current of a circuit.

Amperes or amps (A) are the measurement of current, and show the amount of

charge going through an ammeter every second.

Current is not used up!

Series circuits are circuits with a single loop, so the…

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D: Controlling current
Voltage is the measure of `push' a battery or power supply exerts on the current.

Potential difference is the same as voltage.

Voltage is measured by voltmeters in volts (V).

Bigger voltage = bigger current.

Simple batteries are made from two pieces of different metals in a…

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Variable resistors are used to control the current in a circuit, and are resistors

where their resistance can be changed.

Light-dependent resistors (LDR) are variable resistors that reduce the

resistance as the brightness increases.

Thermistors are variable resistors that change its resistance as the temperature

changes. Most commonly, the hotter…

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E: Potential difference
If the voltage of the battery or power supply is increased, the potential difference

across the components in the circuit also increases.

Voltmeters are connected in parallel.

In parallel circuits, the voltage in each branch is equal to the voltage of the power supply.

In series circuits,…