Analog voltmeters measure voltage or voltage drop in a circuit. They display readings using a needle rather than a digital display. Voltmeters may be standalone devices or a part of a multimeter. Analog voltmeters use a wide variety of means to measure voltage, with d'Arsonval moving-coil galvanometers being most common.
Working Principle of Digital Voltmeter The block diagram of a simple digital voltmeter is shown in the figure. Explanation of various blocks Input signal: It is basically the signal i.e. voltage to be measured. Pulse generator: Actually it is a voltage source. It uses digital, analog or both techniques to generate a rectangular pulse.
2. VTVMs and FET-VMs Vacuum Tube Volt Meter (VTVM) These types of instruments handle DC voltage, AC voltage, and resistance measurements. In this type of voltage measuring device electronic amplifier is used in between the input and the meter. Due to this arrangement the current drawn from the circuit under test is reduced.