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 IP1
Potential /
Voltage
Dividers
How the Potential Divider works…..

In this example of a potential divider, the main component is the Light Dependent Resistor (LDR). When the light level falling on it changes, its resistance value increases or decreases. The other component is the variable resistor, which also has a range of resistance values. These are manually adjusted by turning a conducting wiper pressed against a horseshoe carbon track. Together these two resistors divide, or split up, the power supply voltage (9 volt in this circuit). The voltage seen across the lower resistor is the output voltage of the potential divider circuit and can be used to control the next stage of an electronic system. According to the formula below, the output voltage will increase or decrease as the ratio of the two resistors varies.

NOTE: When you use a potential divider to "turn on" a transistor you will need approximately 0.6 volts at its output or 1.2 volts when connecting to a Darlington Pair.

 

Circuit Diagram

 


In the circuit above, we can use Ohms Law to show how the various voltages and resistances are related to each other.




Below are some Potential/Voltage Divider circuits showing the variable resistors needed to produce approximately 0.5 - 2 volts at their outputs:

 

Light Sensor
Dark Sensor
Heat Sensor
Cold Sensor
Water Sensor
Touch Sensor
Angle Sensor