Voltmeters measure the amount of voltage passing through a circuit. Analogue and digital voltmeters differ in how results are displayed, in level of internal resistance and accuracy. Digital voltmeters are now the most commonly used.
voltmeter image by Roman Sigaev from Fotolia.com
Obvious differences between analogue and digital voltmeters lie in how results are communicated. Analogue voltmeters give readings by moving a needle across a printed background of possible results. Digital voltmeters electronically display results on a LCD screen.
Digital voltmeters operate on a fixed level of resistance, usually around 10 million ohms. Analogue voltmeters can offer resistance as low as 10,000 ohms. An ideal voltmeter would provide an infinite amount of impedance. Such voltmeters do not exist.
Because of the high resistance level of digital voltmeters, they give a more accurate reading, especially at higher voltages. Lower resistance levels in voltmeters can give false readings if the resistance is low enough to increase the circuit's current.