Week 12 : Output Devices

This week's group assignment is to measure the power consumption of an output device.

To do this we chose a 12 V, 0.8A rated DC gear motor and we are going to find its power using 2 experiments.

Experiment 1 :

We used DC power supply equipment available in our lab to power it. We directly connected the dc motor to power supply using the two probes. The advantage is that we can directly monitor the power consumption from the display itself. We may also double check the value by using a multimeter.

Power = Current X Voltage

After giving power we got 12 V and 0.02 A

Power consumption for this motor is 0.240w

Experiment 2:

In this case the power is calculated by attaching a 1 ohm resistor in series with the motor.

The voltage accross the resisitor is measured using a multimeter.

V = 0.023 V
R = 1 ohm

since I = V/R we can find out the current which is 0.023 A.

I = 0.023 A

Next by using the multimeter we have to find the voltage across the working DC motor.

V = 11.94V

Since we have calcuated the current already, the power used by motor is

P = V X I
P = 11.94 X 0.023
P = 0.27 W

Power consumption of the motor is 0.27 W