What Is a Relay?

What Is a Relay?


Welcome to GTV! Today we will take a look
at relays. Relays are switches that open and close circuits when actuated with an electrical
signal. A switch is a device that can open and close a circuit when actuated manually,
typically through a physical action by a person or an object. Relays are used in applications
where it is necessary to control one or more circuits by a power signal that may or may
not be isolated from the circuits being controlled and when manual actuation is not possible
or practical. Here is an electrical diagram of a switch. When the switch is open, the
circuit is open – or off. When the switch is closed, the circuit is closed – or on.
When a switch can be actuated with an electrical signal, the device is then typically referred
to as a relay. The actuation of the relay will change the state of the contacts from
open to closed or vice versus, depending on the contact configuration. Each switch in
a relay is referred to as a pole. Relays may have one or more poles. The number of poles
in a relay indicates the numbers of switches there are contained within the relay. Each
pole may be configured as single or double throw, indicating the number of circuits that
can be controlled per pole. Single throw means that the pole has an open state and a closed
state. The relay will alternate between states when actuated. A double throw pole can control
two circuits and alternate between one circuit being open while the other is closed and vice
versus when actuated. A break is the number of separate places or contacts that a switch
uses to open or close a single electrical circuit. All contacts are either single break
or double break. A single break contact breaks an electrical circuit in one place, while
a double break contact breaks it in two places. Single break contacts are normally used when
switching lower power devices such as indicating lights. Double break contacts are used when
switching high-power devices such as solenoids. To learn more about relays and other products,
please see our other videos on GTV. You can find many relays and thousands of other products and services available at Galco.com.

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Comments

  1. hi I understand a relays with more than 4 points can be made to buzz like a motor..electromagnetic switching, can I know what frequency does it typically buzz or switch when wired to do just that

  2. hi I understand a relays with more than 4 points can be made to buzz like a motor..electromagnetic switching, can I know what frequency does it typically buzz or switch when wired to do just that in nc looping

  3. Thank you for the great video. Needed an introduction to relays as I was checking out binary counters in relation to computer evolution, you helped me tons. Hope you find constructive feedback among the many "constructive" comments about your physical appearance. I work in a field with very few girls and often find it boring and limiting to have so much unusable feedback about my physical appearance rather than my content. I hope you have a good team supporting you in your passion !

  4. I love Relays.
    You can do anything with them.
    Logical circuits.
    Secuencial circuits.
    Combinational circuits.
    They are so nice!!!!

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