FUNDAMENTALS FOR THE BEGINNER
WHAT A PHOTOCELL DOES
Photocells are used to vary the amount of
resistance in many types of electronic devices.
For example, they are used to automatically turn
on lights when it gets dark. By doing this
experiment, you’ll see that the photocell varies
the brightness of the LED, depending on how
much light is hitting its surface.
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
2. Do the Experiment.
Theory: In this circuit, the electronics flow from
the negative side of the battery through the LED,
through the photocell, and back to the positive side
of the battery. The more light hitting the photocell,
the brighter the LED.
Procedure: Connect a nine-volt battery to the
battery snap and observe the brightness of the LED.
Now, cover the photocell with your finger to keep
light from getting to it. Notice that the LED gets
dimmer when you cover the photocell.
You can order parts for this
experiment from their
website as follows:
Check out their website for
courses, basic electronic labs,
and 100s of kits.
Order online at:
Development Tools for PIC® MCUs
microEngineering Labs, Inc.
Phone: (719) 520-5323
Fax: (719) 520-1867
Colorado Springs, CO 80960
With Accessories for $119.95: