13.5- THE POTENTIAL DIVIDER Flashcards
What does a potential divider consist of?
two or more resistors in series with each other and with source of fixed p.d.
In a potential divider, what happens to the p.d. of the source?
p.d. of source divided between components in circuit
Why is the p.d. of the source divided between components in a circuit in a potential divider?
as they’re in series with each other
What can a potential divider be used to do (3)
supply pd which is fixed at any value between zero + source pd
supply variable pd
supply pd that varies with physical conditions i.e. temp or pressure
What is the ratio of pds across each resistor equal to?
resistance ratio of two resistors
What can a sliding contact on wire be moved along the wire to do?
give variable pd between contact + one end of wire
What may be used instead of a resistance wire?
uniform track of suitable material- track may be linear or circular
How can a variable potential divider be used? (2)
as simple audio volume control to change loudness if sound from loudspeaker
vary brightness of light bulb between zero + normal brightness
How can a variable potential divider be used as a simple audio volume control to change the loudness of the sound from a loudspeaker?
audio signal pd supplied to potential divider in place of cell or battery
variable output pd from potential divider supplied to loudspeaker
How can a variable potential divider be used to vary brightness of a light bulb between zero and normal brightness?
use of potential divider enables current through light bulb to be reduced to zero
What if a variable resistor in series with light bulb had been used instead of a variable potential divider to vary the brightness of light bulb between zero and normal brightness?
there would be a current through light bulb when variable resistor is at maximum resistance
What does a sensor circuit produce?
output pd which changes as a result of change of physical variable such as temp or light intensity
What does a temperature sensor consist of?
potential divider made using thermistor + variable resistor
What happens to the source pd with the temp of the thermistor constant? (temperature sensor)
source pd divided between thermistor + variable resistor
What happens to the p.d. across the thermistor if the variable resistor is adjusted? (temperature sensor)
p.d. across thermistor can be set at any desired value
