Anatomical Models
DC Motors
Light (Optics)
Lab Supplies
pH meters
pH Papers
Weights/ Masses

Please select from the list below or the links on the right. 

How to use
Electrical Switches

The most common switching circuits are:

  1. Use a switch to turn On and Off one light bulb

  2. Use two switches to turn On and Off one light bulb

  3. Use three or more switches to turn On and Off one light bulb

  4. Use one switch to alternate Off On two light bulbs

The following diagrams show how switches are used for the above four switching circuits.

Simple Electric Circuit

A simple electric circuit usually consists of one power source (such as a battery), one load (such as a light bulb), one switch and wires connecting them in a closed loop in series. 

Using SPDT or 3-way switches

Three-way switches control lights and receptacles from two points: for example, a light in a hallway that can be operated from the first floor and second floor. The diagram in the right is a simple representation

of a light bulb circuit that can be controlled via two switches.

Switch among the Light Bulbs

You can use SPDT switches to alternate lighting up two different light bulbs. This method is used for some OPEN/CLOSE signs and some manual controlled Red/Green traffic lights. The two light bulbs in this circuit can never be ON at the same time.

Using DPDT Switches

Control One Light Bulb With Three Switches

If you are want to control one light bulb with 3 or more switches, you will need two SPDT switches and some DPDT switches in between.

In the DPDT above when the connection are straight (Z-X and Y-W) or crossed (Z-W and Y-X). In some DPDT switches you will need to make your own cross connection by connecting the throws in a cross form.

How 4-way switches work -- an animation

4 way switch animation

Shown above is an animation of a circuit using three switches to control a light. The center switch is 4-way switch (DPDT), while the outer two switches are 3-way (SPST).

Note that in the above animation, the wires are color coded to indicate their voltage state, rather than the standard NEC color code.

Glossary of Switches:

SPST: Single Pole Single Throw

SPDT: Single Pole Double Throw (Three way switch)

DPST: Double Pole Single Throw

DPDT: Double Pole Double Throw (four way switch)



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List of metals for science experiments


Miniature Light Bulb
Miniature Light Bulbs
Miniature Lamp holder
Miniature Lamp Holders

Metal lamp holders

Test Leads

Plastic Battery Holders

Buzzer, 3-V DC

Crystal Earphone
Simple Switch, Knife Switch
Simple Switch


Banana Jack
Banana Jacks
banana Plug
Banana Plugs
Binding Post
Binding Posts
Dynamo, Bicycle Generator
Dynamo, Generator
Electric Bell
Bells and Buzzers
Magnet Wire
Magnet Wire
Transformer Coil, Educational
Transformer Kit

Knife Switch with plastic screw connectors


UV Lamp/Fixture

Thermoelectric Cooler
Battery Holder, Metal, D Size
Metal Battery Holders

Thermoelectric Generator

Portable UV light (Blacklight)

Push Button Switches

Subminiature light bulbs

Plasma Ball

Educational Buzzer

Electric Bell

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