Solenoids are a well known application where magnetic fields are used to create controlled magnetic force. Solenoids are used in various industries where they [[wysiwyg_imageupload::]]serve the purpose of hydraulic valves, current limiting switch, steering control of heavy machines etc.   This version of Insight details with DC operated tubular solenoid which is often used as an actuator. Comprising of a metallic can, coil, soft iron cored plunger along with insulator coating and connecting wires, linear solenoids are almost noiseless. Depending upon the movement of the plunger, these solenoids can be divided into push type (where plunger goes inside the metallic can) and pull type (plunger comes out of the tin can). Tubular solenoids can work for longer hours without getting their coil overheated or burnt out.  Let’s find out what more constructional and operational features of one such tubular solenoid in this Insight. 

MCBs or Miniature Circuit Breakers are electromechanical devices which protect an electrical circuit from an overcurrent. The overcurrent, in an electrical circuit, may result from short circuit, overload or faulty design. An MCB is a better alternative to a Fuse since it does not require replacement once an overload is detected. Unlike fuse, an MCB can be easily reset and thus offers improved operational safety and greater convenience without incurring large operating cost. The principal of operation is simple. An MCB functions by interrupting the continuity of electrical flow through the circuit once a fault is detected. In simple terms MCB is a switch which automatically turns off when the current flowing through it passes the maximum allowable limit. Generally MCB are designed to protect against over current and over temperature faults (over heating). 

The ding dong sound of the doorbells signifies the presence of someone at the door. Although there are many doorbells available in the markets today with a variety of sounds, the ding dong doorbell still has its share of the market. What makes them interesting is how do they produce this ding dong sound?The ding dong doorbells use the magnetic force produced by an AC solenoid to force an iron rod (called the plunger) to hit against aluminum sheets placed at both sides of the solenoid. This in turn produces the ding dong sound. The DC and AC solenoids are different. The doorbell uses an AC solenoid. When current flows thorough the coil of an AC solenoid, a magnetic field is produced. This magnetic field produces a magnetic force and pulls the plunger in its direction.  

Relay is one of the most important electromechanical devices highly used in industrial application specifically in automation. A relay is used for electronic to electrical interfacing i.e. it is used to switch on or off electrical circuits operating at high AC voltage using a low DC control voltage.Relays are available in different operating voltages like 6V, 12V, 24V etc. A relay generally has two parts a coil which operates at the rated DC voltage and a mechanically movable switch. The electronic and electrical circuits are electrically isolated but magnetically connected to each other, hence any fault on either side does not affects the other side.