I-V Characteristic

Question 1

What does the term ‘I-V characteristic mean?

Answer 1

Refers to a graph which shows how the current flowing through a component as the potential difference across it is increased.

Question 2

What I-V characteristics do linear components have?

Answer 2

Linear components (e.g an ohmic conductor) have an I-V characteristic that’s a straight line.

Question 3

What I-V characteristics do non-linear components have?

Answer 3

Non-linear components (e.g a filament lamp or a diode) have a curved I-V characteristic.

Question 4

Experiment to find a components I-V characteristic

Answer 4

Method:
1) Set up the test circuit
Battery
Variable resistor
Component
Voltmeter
Ammeter
2) Begin to vary the variable resistor. This alters the current flowing through the circuit and the potential difference across the component.
3) Take several pairs of readings from the ammeter and voltmeter to see how the potential difference across the component varies as the current changes.
4) Repeat each reading twice more to get an average potential difference at each current
5) Swap over the wires connected to the battery, so the direction of the current is reversed.
6) Plot a graph of current against voltage for the component

Question 5

What are the I-V characteristics for an ohmic conductor?

Answer 5

Ohmic conductor-
The current through an ohmic conductor (at a constant temperature) is directly proportional to potential difference, so you get a straight line

Question 6

What are the I-V characteristics for a Filament lamp?

Answer 6

Filament lamp- as the current increases the temperature of the filament lamp increases. This means less current can flow per unit potential difference so the graph gets shallower hence the curve.
Look at the picture (S vibes)

Question 7

What are the I-V characteristics for a Diode?

Answer 7

Current will flow only through a diode in one direction. The diode has very high resistance in the reverse direction
Graph- flat then upwards curve