http://www.ck12.org Chapter 17. Circuits
FIGURE 17.15
Figure17.16 shows two voltmeters. Voltmeter 1(V 1 )is reading the potential difference across the 10Ωresistor, and
the Voltmeter 2(V 2 )is reading the potential difference across the 24Ωresistor.
FIGURE 17.16
VoltmeterV 1 readsV 1 =^1009 Vand VoltmeterV 2 readsV 2 =^809 V. See Example 18.3.2.
A voltmeter must have a very high resistance, which means it draws a very small amount of current from the battery
and therefore does not add a substantial amount of current to the circuit while performing its task. That way, the
voltmeter is able to read the voltage across an electronic component without affecting the circuit. If a voltmeter
were placed in series in a circuit, it would not be in danger of burning out like an ammeter in parallel, but it would
seriously reduce the amount of current in the circuit, and be of no use.