Arrange the components in a circuit connecting the power supply to the transformer and itself to a current rectifier. Connect a wire from one terminal of the power supply to one of the two terminals on the input side of the transformer. Connect another wire from the second input terminal back to the power source at its second terminal.
Attach two wires from the transformer's output terminals to the two input terminals of the rectifier. Join the live terminal of the rectifier to the bulb. Complete the circuit by connecting a wire from the negative bulb terminal back to the neutral terminal of the rectifier.
Use the multimeter to measure the output voltage of the transformer right before the rectifier. Refer to the transformer rating and check whether the output corresponds correctly to the input supplied to the transformer by the AC power source. Use an electric motor as the AC power source if you are carrying out an experiment, to minimize risk.
Divide the peak voltage, the maximum voltage reading from the mutimeter, by Pi (3.14159) to get the voltage of the DC current from the rectifier. This calculation is used when a half-wave rectifier is used to convert AC to DC.
Multiply the peak voltage value by two. Divide the product by Pi to get the DC voltage in a case where full wave rectification was used to convert the AC to DC. Current throughout the system remains constant.