The actuator converts electrical signals into corresponding physical quantities, such as motion, force, sound, etc. The actuator is also classified as a transducer because it changes one physical quantity to another and is generally activated or operated by a low-voltage command signal. The actuator can be classified as a binary or continuous device according to the number of stable conditions in its output.
For example, the relay is a binary actuator, because it has two stable conditions, power on and confirm or power off and unlock, and the motor is a continuous actuator, because it can rotate the entire 360 ° movement. The most common types of actuators or output devices are electrical relays, lamps, motors and speakers.
As you have seen before, solenoids can be used to electrically open latches, doors, open or close valves, and various intelligent robots and electromechanical professional applications. However, assuming that the electromagnet plunger is used to operate one or several sets of electrical contacts, everyone has a device called a relay that is very useful. It can be used in countless different ways.
Electrical relays can also be roughly divided into mechanical action relays called "electromechanical relays" and mechanical relays using semiconductor transistors, thyristors, triacs, etc. as their switching devices called "solid state relays" or SSRs.
Electromechanical relay
The term "relay" generally refers to a device that provides electrical coupling between two or more points in response to the application of a control signal. The most common and widely used relay category is electromechanical relay or EMR.
Electrical relay
The most fundamental control of any device is the ability to "turn it on" and "off." The simplest method is to use a switch to interrupt the power supply. Although switches can be used to control certain things, they have their drawbacks. The biggest one is that they have to be manually (physically) "on" or "off". And, they are relatively large, slow and only switch small currents.
However, the vast majority of electrical relays are electric switches, with a variety of shapes, standards and rated powers suitable for use in all categories. Relays can also be equipped with single or multiple contacts in a single package, during which high-power relays for power supply voltages or high-current switches called "contactors" are used.
Regarding electrical relays, everyone only pays attention to the basic working principle of "light-weight" electromechanical relays, and everyone can also be used in motor control or intelligent robot circuits. This relay is used for general electrical and electronic control or switching circuits. It may be directly mounted on the PCB or may be independently connected. The load current during this period is generally a fraction of amperes, up to 20+ amperes. Relay circuits are very common in electronic applications.
Taken out of context, an electromechanical relay is an electromagnetic device that converts a magnetic flux generated by applying a low-voltage electrical control signal of AC or DC on a relay terminal into a pulling mechanical force that operates the electrical contacts in the relay. . The most common method of electromechanical relays includes a booster coil called a "primary loop" which is wound around a permeable core.
The iron core is provided with a fixed part called a yoke and a movable spring loaded part called an armature, which completes the magnetic field circuit by closing the air gap between the fixed electric coil and the movable armature. The armature is hinged or pivoted, allowing it to move freely within the magnetic field of the attack, and then closes the electrical contacts coupled to it. Connected between the yoke and the armature is generally a spring (or multiple springs). When the relay coil is in the "power-off" condition, that is, "closed", the return stroke "resets" the contacts back to their initial suspension orientation.
