Main Difference
The main difference between Relay and Switch is that the Relay is a electrically operated switch and Switch is a electrical component that can break an electrical circuit.
-
Relay
A relay is an electrically operated switch. Many relays use an electromagnet to mechanically operate a switch, but other operating principles are also used, such as solid-state relays. Relays are used where it is necessary to control a circuit by a separate low-power signal, or where several circuits must be controlled by one signal. The first relays were used in long distance telegraph circuits as amplifiers: they repeated the signal coming in from one circuit and re-transmitted it on another circuit. Relays were used extensively in telephone exchanges and early computers to perform logical operations.
A type of relay that can handle the high power required to directly control an electric motor or other loads is called a contactor. Solid-state relays control power circuits with no moving parts, instead using a semiconductor device to perform switching. Relays with calibrated operating characteristics and sometimes multiple operating coils are used to protect electrical circuits from overload or faults; in modern electric power systems these functions are performed by digital instruments still called “protective relays”.
Magnetic latching relays require one pulse of coil power to move their contacts in one direction, and another, redirected pulse to move them back. Repeated pulses from the same input have no effect. Magnetic latching relays are useful in applications where interrupted power should not affect the circuits that the relay is controlling.
Magnetic latching relays can have either single or dual coils. On a single coil device, the relay will operate in one direction when power is applied with one polarity, and will reset when the polarity is reversed. On a dual coil device, when polarized voltage is applied to the reset coil the contacts will transition. AC controlled magnetic latch relays have single coils that employ steering diodes to differentiate between operate and reset commands. It was used in long distance telegraph circuits, repeating the signal coming in from one circuit and re-transmitting it to another.
-
Switch
In electrical engineering, a switch is an electrical component that can “make” or “break” an electrical circuit, interrupting the current or diverting it from one conductor to another.
The mechanism of a switch removes or restores the conducting path in a circuit when it is operated. It may be operated manually, for example, a light switch or a keyboard button, may be operated by a moving object such as a door, or may be operated by some sensing element for pressure, temperature or flow. A switch will have one or more sets of contacts, which may operate simultaneously, sequentially, or alternately. Switches in high-powered circuits must operate rapidly to prevent destructive arcing, and may include special features to assist in rapidly interrupting a heavy current. Multiple forms of actuators are used for operation by hand or to sense position, level, temperature or flow. Special types are used, for example, for control of machinery, to reverse electric motors, or to sense liquid level. Many specialized forms exist. A common use is control of lighting, where multiple switches may be wired into one circuit to allow convenient control of light fixtures.
By analogy with the devices that select one or more possible paths for electric currents, devices that route information in a computer network are also called “switches” – these are usually more complicated than simple electromechanical toggles or pushbutton devices, and operate without direct human interaction.
-
Relay (noun)
A new set of hounds. from 15th c.
-
Relay (noun)
A new set of horses kept along a specific route so that they can replace animals that are tired. from 17th c.
-
Relay (noun)
A new set of anything.
-
Relay (noun)
A series of vehicles travelling in sequence. from 18th c.
-
Relay (noun)
A track and field discipline where runners take turns in carrying a baton from start to finish. Most common events are 4×100 meter and 4×400 meter competitions. from 19th c.
-
Relay (noun)
An electrical actuator that allows a relatively small electrical voltage or current to control a larger voltage or current. from 19th c.
-
Relay (verb)
To release a new set of hounds. 15th-17th c.
-
Relay (verb)
To place (people or horses) in relays, such that one can take over from another. from 18th c.
-
Relay (verb)
To take on a new relay of horses; to change horses. from 19th c.
-
Relay (verb)
To pass on or transfer (information). from 19th c.
“The CCTV cameras relay what’s going on to the headquarters.”
“Can you relay this message to John?”
-
Relay (verb)
alternative spelling of re-lay
-
Switch (noun)
A on and off or direct its flow.
-
Switch (noun)
A change.
-
Switch (noun)
A movable section of railroad track which allows the train to be directed down one of two destination tracks; point.
-
Switch (noun)
A slender woody plant stem used as a whip; a thin, flexible rod, associated with corporal punishment in the United States.
-
Switch (noun)
A command line notation allowing specification of optional behavior.
“Use the /b switch to specify black-and-white printing.”
-
Switch (noun)
A programming construct that takes different actions depending on the value of an expression.
-
Switch (noun)
A networking device connecting multiple wires, allowing them to communicate simultaneously, when possible. Compare to the less efficient hub device that solely duplicates network packets to each wire.
-
Switch (noun)
A system of specialized relays, computer hardware, or other equipment which allows the interconnection of a calling party’s telephone line with any called party’s line.
-
Switch (noun)
One who is willing to take either a submissive or a dominant role in a sexual relationship.
-
Switch (verb)
To exchange.
“I want to switch this red dress for a green one.”
-
Switch (verb)
To change (something) to the specified state using a switch.
“Switch the light on.”
-
Switch (verb)
To whip or hit with a switch.
-
Switch (verb)
To change places, tasks, etc.
“I want to switch to a different seat.”
-
Switch (verb)
To get angry suddenly; to quickly or unreasonably become enraged.
-
Switch (verb)
To swing or whisk.
“to switch a cane”
-
Switch (verb)
To be swung or whisked.
“The angry cat’s tail switched back and forth.”
-
Switch (verb)
To trim.
“to switch a hedge”
-
Switch (verb)
To turn from one railway track to another; to transfer by a switch; generally with off, from, etc.
“to switch off a train; to switch a car from one track to another”
-
Switch (verb)
To shift to another circuit.
-
Switch (adjective)
Pertaining to riding with the front and back feet swapped round compared to one’s normal position.
-
Switch (adjective)
Pertaining to skiing backwards.
-
Switch (noun)
a device for making and breaking the connection in an electric circuit
“the guard hit a switch and the gate swung open”
-
Switch (noun)
a program variable which activates or deactivates a certain function of a program.
-
Switch (noun)
a device which forwards data packets to an appropriate part of the network.
-
Switch (noun)
an act of changing to or adopting one thing in place of another
“his friends were surprised at his switch from newspaper owner to farmer”
-
Switch (noun)
a slender, flexible shoot cut from a tree.
-
Switch (noun)
a set of points on a railway track.
-
Switch (noun)
a tress of false or detached hair tied at one end, used in hairdressing to supplement natural hair.
-
Switch (verb)
change the position, direction, or focus of
“the company switched the boats to other routes”
-
Switch (verb)
adopt (something different) in place of something else; change
“she worked as a librarian and then switched to journalism”
“she’s managed to switch careers”
-
Switch (verb)
substitute (two items) for each other; exchange
“after ten minutes, listener and speaker switch roles”
-
Switch (verb)
beat or flick with or as if with a switch.