FUNDAMENTALS FOR THE BEGINNER
WHAT A POTENTIOMETER DOES
This potentiometer is being used as a rheostat or variable resistor. Its function
is to vary the resistance in electronic circuits and devices. For example, they
are used in radios and TVs to control the volume of the audio in the speaker.
A “pot” can also be used as a voltage divider. By doing this experiment, you
will see that a potentiometer can vary the resistance in a circuit and, in this
case, the brightness of the LED.
1. Build the Circuit.
Using the schematic along with the pictorial diagram, place the
components on a solderless breadboard as shown. Verify that your
wiring is correct.
2. Do the Experiment.
Theory: This electronic circuit consists of an LED, a 100 ohm resistor
(to keep the LEDs from burning out from too much current when the
potentiometer is adjusted to zero ohms), a nine-volt battery, and a
potentiometer. The electrons flow from the battery through the resistor,
through the LED, through the potentiometer, and back to the battery. The
higher the resistance in the circuit, the fewer the electrons that will flow.
Procedure: Connect a nine-volt battery to the battery snap and
observe the brightness of the LED. Now, turn the shaft fully clockwise and then fully counter-clockwise. As you turn the
shaft, the resistance varies through the potentiometer and this will cause the LED to get brighter and dimmer.
red + - black