5.1.10

# Potential Divider

Test yourself

## Potential Divider

Potential dividers can be used to supply constant or variable potential differences from a power supply.

### What a potential divider looks like

• Often in electronics, the power supply has a potential difference that is too high for our intended use.
• Another problem is that we might want a variable potential difference when we only have a constant potential difference power supply.
• A potential divider circuit uses the resistance of a resistor to change the potential difference across a component.
• When the second resistor has a high resistance, there is a reduction of the potential difference across the component.

### Using a variable resistor

• If a variable resistor is now in place of R1, the potential difference across the component can be altered.
• When the variable resistor is set to zero, the component gets the full power supply of potential difference.
• When the variable resistor is set higher, the component gets a smaller share of the full power supply of potential difference.
• The potential difference can be altered to vary the potential difference with time or set it at a lower value than the power supply.

### Using a thermistor

• If a thermistor is now in place of R1, the potential difference across the component is altered based on the temperature of the thermistor.
• When the temperature is high, the thermistor resistance is close to zero and so the component gets nearly the full power supply of potential difference.
• When the temperature is low, the component gets a smaller share of the full power supply of potential difference.

### Using a light dependent resistor

• If a light dependent resistor (LDR) is now in place of R1, the potential difference across the component is altered based on the light intensity incident on the LDR.
• When the intensity is high, the LDR resistance is close to zero and so the component gets nearly the full power supply of potential difference.
• When the intensity is low, the component gets a smaller share of the full power supply of potential difference.