Answer to Question #170580 in Electric Circuits for Innocent

Question

Explain the essential requirement of a

1) voltmeter and

2) ammeter with respect to their resistance

B) explain with circuit diagram how you can construct a multimeter

Answer 1

A voltmeter is a device for measuring the difference in electrical potential (voltage) between two points in an electrical circuit. The voltmeter must be connected in parallel with the voltage source. Therefore, the voltmeter must have a high resistance in order to minimize the current that will flow through the device during measurement.

An ammeter is a device for measuring current in an electrical circuit. The ammeter must be connected in series with the circuit in which the current is to be measured. Therefore, the ammeter must have a low resistance to minimize voltage drop across the device during measurement.

The multimeter combines both devices: a voltmeter and an ammeter. The multimeter circuit is as follows: