A bistable relay, also known as a dual-state or latching relay, is an electrical device that can maintain two stable states without requiring a continuous supply of electrical power. Unlike traditional relays, which rely on constant current to hold a position, a bistable relay uses pulses to switch between states and retains the last position until a new pulse is received. This unique feature offers several advantages in terms of energy efficiency, reliability, and longevity. In this article, we will explore the working principle, advantages, and applications of bistable relays, along with their importance in modern electronic systems.

Working Principle of Bistable Relay A bistable relay operates using two stable states, typically referred to as “ON” and “OFF” positions. It is equipped with an internal mechanism that allows it to switch between these states upon receiving a brief electrical pulse. Once the relay has switched to a new state, it will stay in that state even when the power is turned off, without requiring additional current to maintain its position. The key component of a bistable relay is a magnetic core with two stable configurations. When a pulse of current is applied to one coil, the relay moves to the “ON” state, and when a pulse is applied to the other coil, it moves to the “OFF” state. This action is similar to a mechanical latch that holds the relay’s position until a new pulse is applied. Unlike traditional relays, which require continuous power to stay in a certain state, a bistable relay only consumes power momentarily during the switching process.