How is a voltmeter connected to a component to measure applied voltage?

To measure the voltage, or potential difference, across a component, a voltmeter must be connected in parallel with that component. This allows the meter to sample the electrical pressure without interrupting the normal flow of the circuit. Voltmeters are designed with a very high internal resistance. This ensures that they draw almost no current when connected in parallel, preventing the meter itself from significantly altering the circuit's behavior. Connecting a voltmeter in series by mistake would block most of the current flow and cause the circuit to stop functioning properly.