Electricity
- Created by: Jessica
- Created on: 27-05-10 14:37
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Electrical Circuits.
- Current- Rate of flow of charge.
- Current flows when there is a potential difference. (p.d is a measure of work done, in moving charge around a circuit.)
- Resistance- Opposition to current flow. (measured in ohms.)
- Ohms Law- Current through a resister is directly proportional to pot diff across it, provided temperature remains constant.
- Series- Current stays the same, Pot diff spilts.
- Parallel- Current splits, Pot diff stays the same.
- Ammeter- measures current (put it in series).
- Voltmeter- Measure P.d (put in parallel).
CHARGE (C) = CURRENT(A) x TIME (S)
RESISTANCE (Ohms) = POTENTIAL DIFFERENCE (V) / CURRENT (A)
Mains Electricity.
- UK mains= 230 V, 50HZ.
- Direct current- Batteries/ cells supply current in one direction.
- Alternating Current- Current that constantly changes direction. (the mains supply is alternating.)
- Neutral Terminal- Stays at a P.d close to 0V.
- Live Terminal- ascillates between a possitive and negative potential- current is constantly changing direction.
- Frequency- (Hz) the number of times per second a cycle is completed
- Period- (s) the time taken for a complete cycle.
Plugs
- Brown= Live.
- Blue= Neutral.
- Yellow/ green= Earth.
The wires are made of copper, and have an insulating cover.
- Appliances that have…
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