How to Make Latching Relay | Set Reset Relay

Introduction

Electromechanical relays have been used to switch and control various electrical circuits for decades. However, with the advancement of technology, electronic relays have become more popular due to their small size, low power consumption, and long life. One such electronic relay is the latching relay, which can maintain its state without the need for continuous power supply. In this article, we will discuss how to make a latching relay or Set Reset Relay using a 555 Timer IC, which is a widely used IC in electronics.

In this article, we will learn, how to make latching relay circuit using 555 timer and a few more components, this project can be used in many applications such as motor start stop switch. I hope you will enjoy this project.

Circuit Diagram of How to Make Latching Relay

This project can be designed using a few basic components. The circuit diagram of this project is shown below.

How to Make Latching Relay Circuit Diagram — **Latching Relay Circuit Diagram**

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Components List of How to Make Latching Relay

Following is the list of all components used in this project:

1X 555 Timer IC
1X BC547 Transistor
1X 1N4148 Diode
2x Push Button Nano
1x LED
1x 1k Resistor
2X 10K Resistors
1x 12V Relay
2x 2 Pin Terminal Blocks
1x 3 Pin Terminal Block
JUMPER WIRES

Explanation of How to Make Latching Relay

555 Timer IC:

The 555 Timer IC is a versatile and commonly used IC in electronics. It was introduced in 1971 by Signetics Corporation and is now widely available from multiple manufacturers. It is a simple and robust IC that can be configured in many ways to generate a wide range of different signals, including oscillators, timers, and flip-flops. The 555 Timer IC has three modes of operation – monostable, bistable, and astable.

The latching relay:

A latching relay, also known as a Set/Reset Relay, stores its state even after the control signal is removed. This makes it suitable for applications where power consumption is a concern. The relay is set or reset depending upon the state of inputs S and R, which are connected to the output of the 555 Timer IC.

Working:

In the circuit, the 555 Timer IC is configured in bistable mode, which means it has two stable states – ON and OFF. The output of the 555 Timer IC is connected to the base of a PNP transistor BC547 through a 1KΩ resistor. The emitter of the BC547 transistor is connected to ground, and the collector is connected to the relay coil.

When the circuit is initially powered up, the 555 Timer IC output is low, and the relay is in its OFF state. To set the relay, the S input of the relay is connected to the output of the 555 Timer IC. This causes the output of the 555 Timer IC to go high and turn on the BC547 transistor, which energizes the relay coil and sets the relay contacts. Once the relay is set, the output of 555 Timer IC remains high, and the BC547 transistor remains on, keeping the relay coils energized.

To reset the relay, the R input of the relay is connected to the output of the 555 Timer IC. This causes the output of the 555 Timer IC to go low and turn off the BC547 transistor, which de-energizes the relay coil and resets the relay contacts. Once the relay is reset, the output of the 555 Timer IC remains low, and the BC547 transistor remains off, keeping the relay coils de-energized.

Conclusion

In conclusion, a latching or Set Reset Relay is an electronic relay that can maintain its state without the need for continuous power supply. The 555 Timer IC, which is a widely used IC in electronics, can be used to make a latching relay. The circuit diagram and working of the latching relay using the 555 Timer IC have been discussed in detail in this article. This circuit can be easily assembled on a breadboard using the materials listed above, and it can be easily modified to suit various applications. The applications of this circuit are widespread and can prove useful in controlling various electrical circuits.