What are the advantages when using a digital voltmeter?

Answer 1

The electronic voltmeter has higher input impedance than other voltmeters, such as traditional VOM's. As a result, it loads the circuit under test to a smaller extent, introducing a smaller error in measurement. Many electronic (or digital) voltmeters have an 11 Megohm or 20 Megohm input impedance, as opposed to a typical 20 Kiloohm per volt impedance of a typical VOM with a 50 microampere movement. Some high end electronic voltmeters have an input impedance well into the thousands or millions of Megohms.

Answer 2

The act of connecting a meter to a circuit can in itself, influence voltages and currents in that circuit. Digital meters have what is called a high input impedance, and because of that the influences a digital meter have on the circuit are minimal.