Blog Navigation
Why the Voltmeter is Connected in Parallel and the Ammeter in Series | Explained with Illustrations Measurement principle: Ideally, a measuring instrument must not alter the reading being measured. Loading effect of measuring instruments: What does it mean? E.g. a voltmeter must not load the (voltage) source to alter the actual reading. The above circuit shows how a reading by the voltmeter is altered due to the loading effect as the input impedance of the voltmeter comes in parallel to the load. Open circuit voltage measurement: Another example is measuring the open-circuit voltage with a voltmeter. The internal resistance of the battery or voltage source and the input impedance of the voltmeter form a voltage divider. That will decrease the actual voltage being measured. Why a voltmeter must have a high input impedance: The input impedance of the voltmeter becomes critical for the voltage sources that have high internal impedance. For example, various process ...