Electrical Work

Rate of flow of charge round the circuit
Will only flow through a component if there is a voltage across the component
Measured in amps (A)
Represented by symbol 'I'

Energy transferred per unit of charge (coulomb) that passes
Called potential difference
Measured in volts (V)
Represented by symbol 'V'

Different components are connected in a line, end to end (except for voltmeter)
Current is the same everywhere (size of it depends on total voltage and resistance as V/R=I)
Total voltage is shared between components
Total resistance is the sum of the resistance of each component

Removing one branch does not affect other branches
Voltage is the same across all branches
Current is shared between branches and each branch's current depends on its resistance
Total resistance decreases if you add a second resistor in parallel

The more bulbs, the more resistance so the current decreases
This is because the voltage pushes the current round the circuit and the resistance opposes it so the relative sizes of the voltage and resistance decide how big the current will be

The more bulbs are added, the resistance in the circuit decreases so the current increases

Power= Energy transferred/time

Power= Voltage x Current

Energy transferred= Voltage x Current x time

Charge passed= Current x time

Energy transferred= Charge passed x Voltage

Voltage= Current x Resistance
Ohm's Law

The current through the wire (at constant temperature) is proportional to the voltage

The current through a resistor is proportional to the voltage
Different resistors have different resistances
The steeper the gradient of the line, the lower the resistance

As the temperature increases, the resistance increases, hence the curve

Current will only flow through a diode in one direction

In bright light, the resistance falls and in darkness, the resistance is highest

Temperature-dependent resistor
In heat, the resistance drops
In cold, the resistance increases

Increased temperature means ions vibrate faster
Increased chance of collision with ions
Current is therefore decreased
Decreased current causes increased resistance

Insulators have high resistance

Conductors have low resistance

Total resistance increases
So current decreases