Work/time = power. Each basic lamp, heater, or motor "works" with the electrical circuit. Typically, an open-close switch is all that is required to provide or detach electricity from the source to the circuit. A switch can be any device that opens and closes an electrical connection. It can be as simple as a push button or as sophisticated as a microprocessor controlled automatic gate.
The switch controls how much of the available current flows through it. The more you open it, the more the circuit will "light up". You can use this fact to create different levels of illumination by using multiple switches in series. For example, if you have three 20-watt lamps connected in series with two separate switches, you can turn all four lights on by opening both switches, or just let one lamp shine by keeping the other switch closed.
Switches are used in many appliances that we take for granted today. Toasters, microwaves, and heaters all have switches that control their functions. Even computers have switches called keys that can be pressed to activate certain programs or buttons.
You will usually find a switch located somewhere on the object itself. For example, your refrigerator has several switches located near the door. If you want to know what's inside, you simply open the door and scan the labels on the inside of the fridge.
A switch is a device that is used to break an electric circuit. The circuit is not complete when the switch is in the "OFF" position. The circuit is then referred to as an open circuit. This circuit is not capable of carrying electrical current. A conductor is needed to connect the "ON" position of the switch to the circuit. This connection may be made by hand or using a relay.
The purpose of using a switch is to shut off power to parts of the house you do not need right now. For example, if you are not home and someone flips your switch, the lights will go out even though someone is still at the door. When you return, you can simply turn your switch back on and get ready for company.
Joining or breaking the circuit is what makes a switch useful. If you want to use part of the house that is powered by electricity but don't want strangers to be able to turn it on when they come over, you will need to lock them out of the switch box. This can be done by locking each wire with a tool called a lock-out plug.
If you want people to be able to turn your lights on and off without going into the dark zone, you should leave the switch in the "ON" position.
A switch is a device that is meant to open or close a circuit under regulated conditions. The phrases "open" and "closed" apply to both switches and whole circuits. An "open switch" is one that has no continuity, which means that electricity cannot flow through it. A "closed switch" is one that does conduct electricity--so long as something is pushing against it (such as a button on a doorbell)... When you push down on a closed switch, it stays pushed down. This is called "making the switch stay in its current state." Open switches do not stay in their current state; instead, they go back to being unoccupied if nothing is pressed against them for some time.
In other words, an open switch allows current to flow through it unless something prevents it by making the switch stay in either the on or off position. A closed switch stops all current from flowing through it by keeping the contacts separated.
The term "switch mode power supply" refers to any of several types of electrical circuits that convert alternating current (AC) from your wall socket into direct current (DC) for use by digital devices. These supplies must be designed to operate properly within certain parameters of voltage and frequency. If the input voltage or frequency falls outside of these parameters, the supply may not function properly or at all. Also, a switch mode power supply will shut itself off if the output voltage reaches anywhere near its peak value.