Introduction to the Electric Switch Using Snap Circuits

In this photo Instructable I will give you a brief introduction to Snap Circuits. You'll learn how to build a simple circuit, to understand Direct Current (DC), and how an electric switch works.

Snap Circuits is an educational toy that teaches electronics with solderless snap-together electronic components. Each component has the schematic symbol and a label printed on its plastic case that is color coded for easy identification. They snap together with ordinary clothing snaps. The components also snap onto a 10 X 7 plastic base grid analogous to a solderless breadboard. There are several Snap Circuits kits that range from a few simple circuits to the largest kit that includes 750 electronic projects.

All the kits include manuals printed in color with easy to follow diagrams to assemble the projects. The illustrations for each project look almost exactly like what the components will look like on the base grid when finished. Because the electronic symbol is printed on each electronic component, once the project is completed, it will look almost exactly like an electronic schematic.

To see an example of a Snap Circuits manual, and to review the circuit on which this photo instructable is based go to http://www.elenco.com/admin_data/pdffiles/SC100-RevG.pdf and scroll down to Project  #1.

I like to use Snap Circuits to demonstrate electronic circuits because it is easy for you to understand what’s going on in a circuit as you learn by doing, that is, you learn about electronics by actually building the circuits.

Parts Needed:

1 Battery Holder (2-AA) # 6SC B1
1 Base Grid (11” x 7.7”) # 6SC BG
1 2.5V Lamp Socket (With Bulb) # 6SC L1
1 Slide Switch # 6SC S1
1 Conductor with 3-snaps # 6SC 03
4 Conductor with 2-snaps # 6SC 02

Parts can be ordered from: http://cs-sales.net/sncirepa.html


DC Direct Current

In a DC (direct current) circuit where the electricity can only flow in one direction, we can think of a battery as a storage tank like the water tower in your neighborhood. If nobody turned on their faucet, the water in the tower would just sit there. Forever. Physicists like to think of this as "potential energy." Like a boulder at the top of a hill, it will just sit there, forever, until someone pushes it over the hill or an earthquake shakes it from the top of the hill or erosion undermines it starting it to roll down the hill. When the boulder is rolling down the hill, physicists like to think of this as kinetic energy. So, the water will just sit in the top of the water tower until you turn on the faucet to your water hose. The water will then flow from the top of the water tower through your water hose and then on to the ground. You can then think of the flow of water as kinetic energy and this kinetic energy can be used to do useful work. See picture 2.

When no circuit is connected to your battery, it is like a storage tank, or potential energy. When a circuit is connected to your battery you can think of it as electrons flowing from the positive side of the battery (marked with a "+" sign) to ground (marked with a "-" sign) and you can think of the flow of electrons as kinetic energy that can be used to do useful work such as light up an incandescent bulb.

The Electric Switch

When you enter a dark room, what is the first thing you usually do? Look for a light switch. You flip the switch on and let there be light.

A switch is probably the simplest electronic device. When the switch is off, the circuit is open and no electricity can flow. To use the water pipe analogy Imagine a tank of water with a pipe connected at the bottom. To stop the water from running out of the tank, we can add a valve–more commonly called a faucet. When the valve is off, no water can flow through the pipe. See picture 3.

Conversely, when the valve is on, water can drain out of the tank and flow through the pipe. See picture 4.

The Single Pole Single Throw switch, or “Slide Switch” as it is labeled in Snap Circuits, is similar to a light switch in your home that you flip to switch it on. Electrons then flow from the positive side of the battery (marked with a "+" sign) to ground (marked with a "-" sign). The switch will remain on until you slide the switch to the off position.

Build the Circuit

Pictures 5 through 13 demonstrate the steps to build the circuit. Once the circuit is built, move the slide switch from the off position to the on position and the lamp will light up.

Picture 14 is the electronic symbol for the switch so that you will be able to recognize it on an electronic schematic.