3D Print This Model to Learn How Potentiometers Work

We can’t actually see most electric and electronic components working, so we resort to imperfect analogies — water flow is a popular one — to try and wrap our heads around their functional principles. But if you’re anything like me, you learn best when you can fiddle with something tangible. That’s why this 3D-printable model is great for understanding potentiometers.

Potentiometers are incredibly common in analog circuits, because they let you adjust resistance. You can, in fact, describe them as variable resistors. Even in otherwise digital builds, you might want to use a potentiometer. Connect one to an analog input pin on an Arduino to control some arbitrary parameter, like volume or speed, for example.

But how does a potentiometer actually vary the resistance of a circuit?

That’s what this model demonstrates and it is easy to build. You just have a few parts to print. The other supplies include jumper wires, a battery, an LED, a resistor (anywhere between 100 to 1k ohm should be fine), some aluminum foil, and a pencil.

That pencil is important, because you’ll use its graphite to “draw” the track for the potentiometer and that track is fundamental to its operation. Resistance increases with the length of the track. So, lengthening the track raises the resistance and shortening the track lowers resistance. How do you lengthen or shorten it? By changing the distance between the input and output contact points on the track. A rotary arm does exactly that, moving one contact to different positions on the track to vary the effective resistance of the circuit.

In a real potentiometer, that is all made to fairly precise tolerances to produce predictable output. Here, it is rougher and you won’t be able to predict an exact resistance at any point. But you will be able to see the brightness of the LED change as you sweep the arm along the track.

That makes this perfect for a science classroom, as students can learn how a potentiometer works by seeing it in action for themselves.