10.6 Sensing circuits Flashcards
1
Q
What is a potentiometer?
A
A variable resistor with 3 terminals and a sliding contact. Adjusting this contact varies the p.d between two of the terminals, giving a V out.
Potentiometers can be very compact, making them useful for portable electronic devices.
Sometimes a dial is used instead of a slider, making the potentiometer even more compact.
The potentiometer can also be constructed so that the change in resistance is linear or logarithmic.
2
Q
What does it mean for resistance to be logarithmic or linear?
A
Linear - obeys Ohm’s law, straight V - I graph, constant resistance
Logarithmic - doesn’t obey Ohm’s law, curved V - I graph, resistance changes.
3
Q
Give two advantages of using a potentiometer over a potential divider?
A
- Allows a full range of output potential difference from 0 V to V in.
- Can be very compact (only has one component) hence easily portable.
