Relays Switch Different Circuits
There are two types of relays: mechanical and solid-state. Mechanical relays have a coil wound around a metal core. This coil creates an electromagnetic field, which opens and closes the contacts. Solid-state relays are usually used for high-speed switching, such as the transistors found in computers.
Relays are also classified by their contact forms. One type of contact is referred to as a normally-open (NO) contact, while another type is a normally-closed (NC) contact. When the contacts of the relay are open, their resistance is measured in Mega-Ohms. When the contacts are closed, the resistance is zero.
Electronic relay switch are designed as single epoxy resin-molded solid-state modules and are used for high-speed switching applications. Another type, called a power factor relay, works when the power factor of an AC circuit is higher than a predetermined value. These relays are a good choice for power factor correction applications.
Depending on the situation, different types of relays switch different circuits. Some are sensitive, while others are not, but all have a basic design that provides protection to circuits. In a typical circuit, a relay is composed of three components: a determining component that calculates the variation between the actual amount and the predetermined value.
Different Types Of Relays Switch Different Circuits
The main difference between SPST and DPST relays is the pole configuration. A DPST relay has four poles, while an SPST relay has one. The designations NO and NC remove ambiguity between the two types. When ordering a relay, make sure to know the type of wiring it needs to accommodate.
Relays are used to control several circuits using minimal power signals. Their first use was in long-distance telegraph circuits as signal repeaters. A reed relay will refresh the signal that came from one circuit by sending it on another. Its usage expanded to telephone exchanges and early computers.
A simple electromagnetic relay consists of a soft iron core with a movable iron armature. The coil provides a low-reluctance path for magnetic flux. A movable iron armature closes the electrical contacts when the relay is switched on or de-energized.
Contactor relays are a special type of electrical relay that switches a large amount of electrical power. They are a good choice for controlling electric motors as they generally have multiple contacts. This type of relay can also be used in regulating a motor. Its contacts are less sensitive and faster than electromechanical relays.
Solid-state relays are another type of relay. Solid-state relays use transistors and are often the most compact of all types. They also have a higher power gain than other types of relays. Solid-state relays are faster at switching than the other two types, making them an excellent choice for high-speed switching.
Solid-state relays can be divided into two main types: photo-coupled and transformer-coupled. Photo-coupled SSRs use a semiconductor component to detect light. Photo-coupled SSRs also have higher switching speeds and less noise than electromechanical relays.
