Current calculations

The first way to use Ohm’s Law is to find current values in dc circuits. In order to find the current, you must know the voltage and the resistance, or be able to deduce them. Refer to the schematic diagram of Fig. 1. It consists of a variable dc generator, a voltmeter, some wire, an ammeter, and a calibrated, wide-range potentiometer. Component values have been left out of this diagram, so it’s not a wiring diagram. But values can be assigned for the purpose of creating sample Ohm’s Law problems. While calculating the current in the following problems, it is necessary to mentally “cover up” the meter.

Fig. 1: Circuit for working Ohm’s Law problems.