Question

Explain the working of DVM with block diagram.

Answer 1

Unknown voltage signal is fed to the pulse generator which generates a pulse whose width is proportional to the input signal.

Output of pulse generator is fed to one leg of the AND gate.

The input signal to the other leg of the AND gate is a train of pulses.

Output of AND gate is positive triggered train of duration same as the width of the pulse generated by the pulse generator.

This positive triggered train is fed to the inverter which converts it into a negative triggered train.

Output of the inverter is fed to a counter which counts the number of triggers in the duration which is proportional to the input signal i.e. voltage under measurement. Thus, counter can be calibrated to indicate voltage in volts directly.