Question T7D02
From subelement T7 - T7D
How is a voltmeter connected to a component to measure applied voltage?
Why is this correct?
A voltmeter measures the electrical potential difference (voltage) across a component, so it must be connected in parallel. This allows the voltmeter to measure the same voltage that appears across the component without interrupting current flow. Connecting in series would place the voltmeter in the current path, disrupting circuit operation and preventing accurate voltage measurement across the intended component.
Memory tip
Remember the measurement rule: voltage measurements need parallel connections, current measurements need series connections. Think 'voltage across, current through' - you measure voltage across components (parallel) and current flowing through circuits (series).
Learn more
In practical amateur radio work, you'll frequently measure voltages across components like resistors, capacitors, and transistors to troubleshoot circuits. A voltmeter's high internal impedance ensures minimal circuit loading when connected in parallel. This measurement technique applies whether checking power supply voltages, bias voltages in amplifiers, or signal levels across antenna tuning components. Understanding parallel voltage measurement is fundamental for station maintenance and circuit analysis.
Think about it
Why do you think connecting a voltmeter in series with a component would give you an incorrect voltage reading?