How is a voltmeter connected in a circuit to measure voltage?

A voltmeter is designed to measure the voltage across a component in a circuit, and it must be connected in parallel to that component. When connected in parallel, the voltmeter can accurately detect the potential difference (voltage) across the component without significantly affecting the circuit. This is because a voltmeter has a very high internal resistance, which minimizes the current that flows through it. As a result, it can measure the voltage accurately without drawing much current from the circuit, thus not altering the circuit's behavior.

Connecting a voltmeter in series, on the other hand, would result in it being part of the current path, which would lead to improper voltage readings and could potentially damage the voltmeter or affect the entire circuit. Similarly, whether in series with the power source or in parallel to it, would not isolate the measurement to just the voltage across the specific component intended for analysis, hence not providing a correct measure of that component's voltage.