Topic 9 Flashcards
An electric current is the rate of
Flow of charge
Unit for charge
Coulombs C
One ampere or amp A is one
Coulomb of charge per second
Charge =
Current x time
A x s
When will electric current flow?
In a closed circuit when there is a source of potential difference
Describe how ammeters should be connected with components in circuits
Ammeters should always be arranged in series with the component to be measured
Energy transferred =
Charge moved x potential difference
What does ohms last state
How the current through a component related to its resistance and the potential difference across it
The resistance of a component is a way of measuring how
Hard it is for electricty to flow through it
Unit for resistance
Ohms
Resistance up current
Down
The resistance of a circuit can be changed by putting different
Resistors into the circuit or by using. Sbariable resistor. The resistance of a variable resistor can be changed using a slider of knob
Ohms law states that the size of the current, i, flowing through a component of resistance, r, is
Directly proportional to the potential difference, v, across the component at constant temperatures
Equation for Omhs law
Potential difference = current x resistance
Components that obey ohms law are said to be
Ohmic comduxtors whereas those that do not obey are non-ohmic
