Topic 2a - circuits (2. resistance and I-V characteristics)

Question 1

what is resistance

Answer 1

anything in the circuit which reduces the flow of current. measure in ohms.

Question 2

formula for potential difference

Answer 2

V = IR
V = potential difference (volts, v)
I = current in amperes 
R = resistance in ohms

Question 3

what is an ohmic conductor?

Answer 3

e.g. a wire or resistor, resistance doesn’t change with the current. at a constant temperature the current flowing through an ohmic conductor is directly proportional to the potential difference.

Question 4

what type of components are not ohmic

Answer 4

diodes and filament lamps as their resistance changes with the current going through them.

Question 5

I-V characteristics of an ohmic conductor

Answer 5

directly proportional to potential difference. so you get a straight line I-V characteristic. different resistances means straight lines with different slopes.

Question 6

what are IV characteristics

Answer 6

show how the current varies as you change the potential difference across a component.