In this video, we’re going to be looking at the potentiometer. Its resistance can vary up to one kilo-ohm and has a one-watt rating.

There are three terminals. The two side terminals connect to the full resistance, and the middle terminal is common. By connecting leads across either of the side terminals and the common terminal, we can adjust the resistance by turning the knob. Notice that with the terminals I have connected, when I turn the knob clockwise the resistance decreases, and when I turn the knob anti-clockwise the resistance increases.

In order to demonstrate the operation of this potentiometer, we’re going to connect a circuit with the LED. So first I’m going to set the supply to five volts. I’m going to connect a wire between the positive supply terminal and the common terminal of the plot. Then I’m going to connect a wire between one of the side terminals of the plot and the positive terminal of the LED. To complete the circuit, I’m going to connect a wire between the negative terminal of the LED and the negative supply terminal. I’m also going to monitor the voltage across the LED with my multimeter. When I turn the supply on, you will notice that the LED lights up. In the configuration that I have it set up in, you will see that when I turn the knob clockwise, the LED becomes brighter because there is more voltage drop across it. And then when I turn the knob anti-clockwise, the LED becomes dimmer because there is now less voltage drop across it.

This is a low-wattage potentiometer, so please make sure to stay within its power rating, especially when you set the potentiometer to a low resistance. Do not connect it directly across the supply terminals or in series with the lamps, as this may damage the device.

That’s all for now. If you have any questions or feedback in regards to this video, please don’t hesitate to email or call using the phone number shown onscreen. If you want to know more about the other components, please feel free to see our other videos. And as always, thanks for watching.