Conversion of electrical current in a circuit

Electric Current and charge

-electric current(I) is the flow of electric charge(Q)(they are proportional)

-current is measured in amps(on a ammeter which is connected in a series to the component)

-electric charge is measured in and coulombs(C) and measured by:

charge flow = current x time

Q = It

the current in a single, closed loop of a circuit is the same in all points in the loop

as the current has no where to go(e.g. no branches travel down)

Resistance and potential difference:

-resistance(R) is measured in ohms and the resistance of a component is the measure of how it resists the flow of charge

-the component is the called the resistor

higher the resistance:

  • the more difficult it is for charge to flow

  • the lower the current

-potential difference(measured in volts on voltmeter) tell us the difference in electrical potential from one point in a circuit to another

the bigger the pd across a component:

  • the greater the flow charge through the component

  • the bigger the current

current, potential difference and resistance is linked by:

potential difference = current x resistance

V = IR (the voltmeter in a circuit is connected parallel to the component)

resistance of a ammeter:

  • ammeter should ideally have a low resistance to avoid disturbing the current in the circuit, ensuring that the current measurement is as accurate as possible.