In this lesson students explore potentiometers, a special kind of resistor that allows us to control how much electricity flows through a circuit by simply turning a knob. Students begin by reviewing what resistors do, then learn how potentiometers add flexibility by offering a smooth range of control. They practice reading the three potentiometer pins, wiring it correctly on a breadboard, measuring its output with a multimeter, and finally controlling the brightness of an LED. The tone of the lesson stays warm and supportive, guiding students step by step so that even beginners feel confident working with this new component.
Student Learning Goals
By the end of this lesson students will be able to: • Explain what a potentiometer does and how it varies resistance
• Identify the three potentiometer pins: voltage, ground, and wiper (output)
• Place a potentiometer correctly on a breadboard
• Measure potentiometer output using a multimeter
• Use a potentiometer to control the brightness of an LED
• Read a simple circuit diagram involving a variable resistor
Materials Needed
Breadboard
Potentiometer
Jumper wires
Battery pack with batteries
Multimeter
LED
Journals and pencils
Teacher Preparation Notes
Review how the three pins of a potentiometer work so you can explain them slowly and clearly. Prepare a working example on your breadboard before class so you feel comfortable demonstrating the twisting action and voltage changes. Ensure students have working LEDs and a multimeter set that can measure DC voltage.
Safety Notes
We disconnect the battery pack before rearranging wires.
We keep jumper wires organized to avoid tangling.
We do not bend LED legs repeatedly.
There is virtually zero electrical shock risk using a small battery pack and breadboard.
Warm Up Activity
Hold up a potentiometer and ask:
What do you think this little knob does inside a circuit?
Let students guess. Explain that today they will discover how this tiny part lets us control electricity like a dimmer switch.
Lesson Flow
Step One: Review Resistors
Remind students that resistors slow the flow of electricity to protect sensitive components. Tell them a potentiometer is simply a resistor that can change its value as you turn the knob.
Journal prompt:
Why might it be useful to change resistance during a project?
Step Two: The Three Pins
Explain each pin gently: • One side pin connects to ground.
• The other side pin connects to voltage.
• The center pin is the wiper, which sends out whatever value the knob is set to.
Use a simple diagram so students can see how the wiper moves between ground and voltage.
Step Three: Placing the Potentiometer on the Breadboard
Show students how the potentiometer legs fit into the terminal strip area next to the power busses. Remind them not to place it directly into the bus lines.
Have them press it gently into place.
Step Four: Connect Ground and Power
Guide students to: • Connect a black jumper from ground to one side pin of the potentiometer.
• Connect a red jumper from the positive bus to the other side pin.
Explain that now the potentiometer has its full range of power.
Step Five: Measuring the Output with a Multimeter
Show how to connect the multimeter probes: • Black probe to ground bus
• Red probe to the center pin (wiper)
Students turn the knob and watch the voltage go from low to high.
Journal prompt:
What voltage did you see at the lowest and highest settings?
Step Six: Adding an LED
Students insert their LED into two separate vertical rows. Remind them that the long leg is the positive side.
Add: • A wire from the wiper (center pin) to the LED’s long leg row.
• A wire from the LED’s short leg to the ground bus.
Explain that the potentiometer now controls how bright the LED becomes.
Step Seven: Twist and Observe
Let students turn the knob slowly. The LED should brighten and dim smoothly. Encourage them to explore how small turns make small changes in light.
Step Eight: Understanding the Diagram
Show a simple circuit diagram with the potentiometer feeding the LED. Trace the path together and reassure students that diagrams become easier with practice.
Teacher Notes for Each Slide
Slides 1–3 Introduce potentiometers and review resistors.
Slides 4–7 Three-pin explanation: move slowly.
Slides 8–12 Breadboard wiring: show each step clearly.
Slides 13–16 Multimeter measurement: pause to support students.
Slides 17–end LED control: celebrate success.
Independent or Group Activity
Have students design a small circuit that uses a potentiometer to control something else: motor speed, LED brightness patterns, or even sound if a buzzer is available.
Vocabulary and Concepts
Potentiometer A variable resistor with a turning knob
Wiper The center pin that outputs the adjustable voltage
Resistance A measure of how much electricity is slowed down
Wrap Up
Ask:
What did you notice when turning the knob?
How might a potentiometer be useful in a real project?
Exit Ticket
Draw the three potentiometer pins and label voltage, wiper, and ground.
Quiz
- What does a potentiometer do?
- Which pin sends out the adjustable voltage?
- Why do LEDs need to be wired correctly?
- What tool did we use to measure the output?
- How can a potentiometer change an LED’s brightness?
Teacher Reflection
Did students understand the three-pin layout?
Was multimeter use comfortable?
What might you demonstrate more slowly next time?