Experiment 1 - Reference Voltage at the Comparator

The comparator compares two voltages. In this first step you connect a reference voltage to the comparator, with which you compare voltages.

In the circuit shown you connect the positive input (pin 2) of the comparator to a voltage divider consisting of two equal resistors R1, R2.

Circuit diagram reference voltage comparator.

Reference voltage at a comparator circuit. (Enlarge)

With a multimeter you measure at the positive input (pin 2) a voltage of V_Ref = 4,5 Volt. The light emitting diode LED1 remains dark.

This voltage is now your reference voltage against which you compare the voltages in the coming experiments...