Experiment 5 - The Voltage Comparator

To understand how you can build a Schmitt trigger using a voltage comparator, you should first take a look at the voltage comparator circuit.

A voltage comparator compares two voltages and returns as a result which voltage is higher.

Consider the circuit with the LM311 voltage comparator...

Circuit diagram voltage comparator.

Voltage comparator circuit. (Enlarge)

Turning on the potentiometer P1...

• If the voltage at the (+) input is greater than that at the (-) input, LED1 remains dark.
• If the voltage at the (+) input is smaller than that at the (-) input, LED1 lights up.

The switch-on and switch-off points coincide...