Electrical Switches Key Terms

Make connections with the language of electrical switches
By Trisha Schulz Thinking of working in the electrical field? Not only will you need to gain education on safety and mechanical aspects of the job, you'll also need to have a vast working knowledge of how electrical switches work. When it comes to electrical switches, there's a lot to learn, from terminal types to the different kinds of switches, all with different functions. An understanding of electrical switches will be helpful no matter what type of job you want to pursue in the industry. Start with the basics of electrical switches by studying the following key terms.
 

Key lock switch

Just as its name indicates, a key lock switch requires a key be used to unlock the switch and let it perform its function, such as turning the unit off or on.
Try: Check out the description of key lock switches given by Electronics-manufacturers.com.

Rotary switch

A rotary switch gets its name because it actually contains a rotating shaft. That shaft, attached to an electrical terminal, hooks up to another terminal to make the electrical connection or to disconnect and break the connection.
Try: Review different models and features of the rotary switch through Multi-tech Industries.

Toggle switch

A toggle switch is hinged and can offer two positions: on or off. The switch works by using a toggle joint with a spring on it to push through an attached lever to either open or close access to electric power.
Try: Review this Directron.com article detailing a toggle switch and how it is used in a computer application.

Single pole single throw (SPST)

A single pole single throw switch is a two-terminal switch that pulls electricity from only one circuit.
Try: View an Expert Village video to learn more about single pole single throw switches.

Single pole double throw switch (SPDT)

The element in a single pole double throw switch contains one terminal that is normally open, one common and one normally closed. This type of switch allows electricians to either wire the circuit as normally open or normally closed, depending on how the light will be used.
Try: See the differences between single pole double throw and single pole single throw switches, along with diagrams, at The Electronics Club.

Circuit protection

Circuit protection refers to the overall concept of safeguarding electrical circuits to avoid dangerous situations such as over-currents or over-voltages.
Try: Check out this ControlGlobal.com article about power supplies and circuit protection.