This control switch can be a transistor, microcontroller, or anything that performs switching operations. In 5V relays, pin 1 is connected to the positive terminal of the 5V DC supply, and pin 2 is connected to the negative terminal or ground through a control switch. In the case of 5V relays, the coil voltage must be 5 V. Let’s take a look at how 5V relays generally operate. Depending on the application, the other end of the load is connected either to normally closed or normally open pins. Usually, the common terminal is connected to the load end where the current enters the load. The other three pins are common (COM), normally closed (NC), and normally open (NO). The ends of an inductive coil that acts as an electromagnet when energized corresponds to pin 1 and pin 2. Most relay modules come with common five pins. They are available as modules in the market.

Relays are essential components in automatic control circuits, load switching systems, star-delta converter-based motor speed controls, under-voltage protection, and over-voltage protection. A relay is triggered for low currents however, they enable the control of high power systems. Relays allow easy control of devices that are remotely placed.

In this article, we will discuss relay and pin configurations, the operation of 5V relays, and the importance of flyback diodes in 5V relays. Luckily, coil de-energization can be prevented by placing a reverse-biased diode, called a flyback diode, across the coil. If the coil voltage is 5 V, then the relay is called a 5V relay.Ĭoil energization is the key to building an electromagnet, so de-energization of a coil causes harmful effects on associated relay components.

The coil is energized with DC voltage and is specified as coil voltage in the datasheet. Relays are electrically operated switches that function with the help of an electromagnet, which is usually formed by a coil. Relays are an essential component in automatic control circuits The most common coil suppression technique in relays is to connect a reverse-biased diode in parallel with the relay coil.įor a 5V relay, the reverse voltage rating of a flyback diode should be at least the coil voltage or working voltage. The voltage generated during relay coil de-energization may be large enough to cause arcing in the control switch contacts and can reduce the switch life.

Common pin relay