Reed Relays

Reed relays are contact relays which core components are reed switches. They are typically used to switch small signals. Reed relays are usually controllable only by a magnet, thereby making them suitable for applications in which contact isolation, repeatability and reliability are required features.

The 3501-12-711 reed relay is a single-pole, single-throw (SPST) device designed for remote control applications. It is an encapsulated unit, using a magnetically-controlled reed switch for the contact actuation. It has a contact rating of 0.5 amps at 12 Volts DC. The contacts are normally open, with a nominal close-in time of 2 ms.

Application Field

The 3501-12-711 reed relay is versatile, offering a variety of applications. It can be used in any situation where the reliable control of a contact is required, including automotive systems, industrial relays, circuit boards, and many consumer products. Generally, reed relays are used to switch small signals, and can be used for switching circuits with analog signals for functions such as gain control.

Working Principle

Reed relays operate on a basic principle. A small contact is held in a hermetically-sealed capsule filled with an inert gas. When a small electric current is applied to the coil of the relay, a magnetic field is created which attracts the contact and causes it to close. This closes the circuit and allows an electrical current to pass through the contacts. This closing of the circuit is referred to as activating the relay.

When the current is no longer applied, the contact returns to its open position, interrupting the circuit and deactivating the relay. Reed relays are versatile and can switch both AC and DC, so they are suitable for a wide range of applications. Additionally, the hermetically-sealed environment in which the reed switch operates ensures that the reed relay will not be affected by dust or dirt, providing reliable performance in hostile environmental conditions.