Learner Resource

Ammeters and Voltmeters; why do we put them where we put them?

IntroductionWe have now seen several examples of the use of ammeters and voltmeters, and we can see that voltmeters always go in parallel and ammeters always go in series. Why?

Clue: how do components in series and in parallel affect the voltage and current in a circuit?

Activity Learners should be encouraged to ask why we cannot measure amps in parallel or volts in series, and how we can measure either without noticeably affecting the circuit. In some cases, the word ‘noticeably’ might be important. Knowledge of how voltage and current are affected by components in series and in parallel should be brought in to the explanation.

Version 1 1 © OCR 2015Electric circuits

Extension activities/questions:Encourage learners to speculate as to how one might create a voltmeter or ammeter and what might be inside them.

Version 1 2 © OCR 2015Electric circuits

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Page 2: Ammeter and voltmeter, RealVector/Shutterstock.com

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