Prototyping & Experimenting When you want to built an electronic circuit, you can certainly connect things together using clip leads like you did in other electronic circuits.  But, most circuits need dozens of wires.  If you can imagine trying to clip 50 clip leads to terminals without having a single one come off or touch another that it shouldn’t, you’ll probably guess this won’t work very well.  So, we use some other ways to wire up circuits that are especially good while we’re experimenting.

Electronics are used everywhere these days. Of course, we see them in TV’s and stereos, computers, cell phones and iPods. But they’re also a part of car keys and even mailing labels on boxes.

They’re used to explore the surface of mars in space probes and give sight to blind people. All these things use transistors, resistors, chips and more – just what we’ll be talking about in this unit. So, let’s get started.
Let’s start with the breadboard.   The breadboard lets you wire up circuits in a neat and organized way, and without soldering.  They also make it easy to change or fix your circuit, add more components and also replace parts if you damage them while experimenting (this happens semi-regularly when you’re designing a new circuit).

Scientific Concepts:

  • Identify and describe how basic electronic components like resistors, capacitors, transistors, diodes, switches, relays (and more) work
  • Be able to follow an electronic schematic diagram to build a circuit
  • Learn how to ‘breadboard’ a circuit
  • Understand when and how to use series and parallel circuitry
  • Create really cool projects like audible light probes, flashing circuits, and light-detecting circuits as well as human-interactive circuits (the Lie Detector)
  • Hone your troubleshooting skills, which are essential if you’re going to be a scientist of any kind


Select a Lesson

Bread Board Basics
Although you can’t see electricity, you can certainly detect its effects – a buzzer sounding, a light flashing, a motor turning… all of these happen because of electricity. Which is why electricity experiments are among the most frustrating. You can’t always tell where the problem is in a circuit that refuses to work right. We’re …
Light Actuated Circuit
In this circuit, we’re going to use a special kind of resistor, called a CdS photocell to detect light and dark.  When light is shined on the photocell, the LED will light up.  When it is dark, the LED goes out.  And with just a little light, the LED is dim.  Remember the explanation of …
Light Deactivated Circuit
Make sure you’ve already made the Light Actuated Circuit before starting this project! Photoresistors (also called CdS photocells) are made of a material that reacts with light, very similar to solar cells.  When light hits the material, it knocks a few electrons loose. When you hook up the cell to a circuit, the electrons now …
How to Read Schematics
Do you remember the first time you tried to read a map? There were all those weird symbols and curving lines that you had to figure out before you could get anywhere. Electric circuits are kind of the same way… people use schematic diagrams to write down how their circuit is wired so others can …
Flashing Circuit
This Flashing Circuit used to be a real ‘wowser!’ with students before LEDs become commonplace (around 1995). You’re going to build a circuit that has a control knob that will allow you to set the flash speed of the LED. You can try different LEDs or mini-lamps to see what kind of an effect you …
Audible Light Probe
Resistors look like candy-striped hot dogs. Their job is to limit current to keep sensitive electronics from being overloaded. If you break open a resistor, you’ll find a pile of graphite. If you have a digital multimeter, draw a line on a sheet of paper with a graphite pencil, and place one probe near the …
Lie Detector Circuit
Lie Detectors are electronic circuits that are able to measure your skin’s resistance. When you sweat (or if your skin is wet), the resistance is different than if it’s dry. However since most people don’t sweat when they lie, this type of detector isn’t the most reliable type of detector around, but it’s one of …
Flashlight Laser Tag
This super-cool project lets kids have the fun of playing tag in the dark on a warm summer evening, without the “gun” aspect traditionally found in laser tag. Kids not only get to enjoy the sport, but also have the pride that they build the tag system themselves – something you simply can’t get from …