What is a relay, how many types and how do they work?

What is a relay?

A relay is an electronic switch or a switch that uses electrical current to control it. There must be an electrical circuit on the Input side to send electricity to the relay. In the relay there is a coil. when there is an electric current into the coil generates magnetic energy To pull or push in order to cut or connect the electrical circuit on the Output Side or that is, the Relay acts as a control by relying on the operation of the Circuit on the Input Side, for example, if the temperature is hotter than 28 degrees, release the electric current. relay so that the relay connects to the circuit on the Output Side to turn on the air conditioner So we can apply relays. To control various circuits in many electronic technicians. Instead of using the on/off switch

The key components of the relay are as follows.

1. The coil (coil) acts to receive voltage from the controller circuit or controller to induce electric current to change into magnetic energy in order to attract the contact (contact) to change position.
2. The contact (contact) acts like a switch that determines the direction of the electrical supply to the device we want.

How does the relay work?

Relays have working principles according to the form of standard connection points, which are available in 2 types.

1. NC (Normally Close) or Normally Closed connection point

The NC point stands for normal close, meaning that it is normally closed, that is, if there is no power supply to the coil (coil), this contact will be connected to the C point. We generally connect this point to a device or electrical appliance. who want to work all the time

If based on the example, it can be seen that the water pump will continue to release water until the water level rises to the point where the circuit is connected and sends electricity to the relay. Then the relay cuts off the electrical circuit that feeds the pump. for the pump to stop working

2. NO connection point (Normally Open) or normally open

The NO connection stands for normal open, meaning that it is normally open, ie if there is no power supply to the coil (coil), the contact will not be connected to the C connection. In general, we usually connect this point to equipment or appliances. Electricity required to operate for a limited time only

Based on the example, it can be seen that if the temperature heats up to the point where the Bietallic Strip is bent to touch the circuit, electricity can flow to Leeey. causing the magnetic force to cause another circuit to light up make the fan turn on

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