Transcript Foundations of Technology Potentiometer Teacher Resource

Foundations of Technology
Potentiometer
Teacher Resource Unit 4 Lesson 4
© 2013 International Technology and Engineering Educators Association,
STEMCenter for Teaching and Learning™
Foundations of Technology
Objective:
1.
Demonstrate that a potentiometer is able
to change its resistance.
You will need the following parts from your kit:
1.
2.
3.
4.
5.
6.
Breadboard
100 ohms resistor (brown, black, brown, gold)
anode
1 LED (light emitting diode)
cathode
1 Potentiometer
Flat side Shorter lead
9 volt battery lead
9 volt battery
Use this schematic to construct the experiment.
Flow of current
This wire should hang free
+
9 volts
100 ohms
Flow of current
Quick Check:
Your circuit should like this one.
1.
2.
3.
4.
This circuit will light the LED.
The 100 ohm resistor is put in this circuit to keep
the LED from burning out.
The potentiometer is a device that when adjusted
will change its resistance.
The greater the resistance, the dimmer the LED
will be.
You may find a potentiometer on your CD-player to
adjust the volume from the speakers.
1.
2.
3.
4.
Connect the 9 volt battery.
Observe the brightness of light from the LED.
Turn the shaft on the potentiometer.
Observe the change in brightness of light from the
LED.
Troubleshooting:
1. If the LED does not light up, check to make sure it is in correctly.
2. Check the battery. Does it have voltage?
3. Are there any breaks in the circuit?
4. Are you using the correct wires on the potentiometer?
By completing this experiment, you should have
noticed the light from the LED grew dimmer as you
increased the value of the resistance in
potentiometer.
In complete sentences, write what you learned about
a potentiometer in a circuit.