DC RELAYS

 

DC RELAYS

Introduction:

A relay is an electromechanical switch that uses voltage to move the mechanical switch on or off. The voltage rating, when achieved by a coil, energizes the coil inside and turns the mechanical piece. Relays have two common modes known as normally open (NO) and normally closed (NC). When the mechanical switch is on NC the switch is closed, and the path is connected, whereas in the NO the path is normally open, and the relay needs to be energized to complete the path.

Difference Between AC And DC Relays:

The core difference between the AC and DC relays the resistance of the coil. The AC relays have lower resistance, and they use induction reactance. The reactance induced offers more impedance and hence lowers the current in the coil eventually. To have lower resistance, the number of coils compared to the DC relays is kept lower.

In the DC relays, the current drawn is directly determined b the coils. The current in the DC coil is determined via ohm’s law.

V = I x R

A 12V DC relay with a 120 ohms resistance will result in a current draw of 0.1 amps.

Benefits Of Using Relay:

·         The first and foremost advantage of using a relay is the circuit can be operated remotely, which increases human safety.

·         The contact can be controlled via voltages level at a higher speed than manual switching.

·         The high level of voltage circuits can be controlled via small voltage level relays, which makes them really useful in high voltage applications.

·         Multiple relays can be used using a single signal, making it convenient and efficient in the control device.