ElectroMech Lab

What is a Bistable Relay? A bistable relay, also known as a latching relay, is an electromechanical device that has two stable states. Unlike conventional relays that require continuous power to maintain their state, bistable relays can hold their position without a constant power supply. This characteristic makes them energy-efficient and suitable for applications where power consumption and space are critical factors.   Operation Principle The operation of a bistable relay is based on the principle of mechanical latching. It consists of two coils, a set coil, and a reset coil, which control the relay's two stable positions. When current flows through the set coil, it generates a magnetic field that attracts the relay's armature, causing it to physically move and latch into position. The relay remains in this state even after the current is removed.   Similarly, applying current to the reset coil generates an opposing magnetic field that pulls the armature back t

Arduino millis() vs delay() Arduino is a hardware & software based platform, which gives a great opportunity to the hobbyist, students to learn and create interesting projects. However, by being expert with Arduino you can make advance projects as well.   In this article I am going to discuss about delay and millis() functions. When we can use these functions to generate delay.   What is the millis() & delay() function in Arduino? This function gives the time value in milliseconds since board was started. Advantage of using this function is program does not stop during delay. Other task continue to take place. While if you use ‘delay’ function, then program is paused for the time set in delay function. For example. If I use delay (5000) Then program will be paused for 5000 milliseconds or 5 seconds. To save the value of millis(), you should use variables of ‘unsigned long’ type because the value is in milliseconds and it increases very fast. For ex

Many times we need to control a single electrical machine from different location, means we can make the Fan (for example) from three different locations. We can do this with the help of PLC, Smart Relay. I am using Zelio Smart Relay, SR3B261B. Open the ZelioSoft2 and select for Ladder programming. Select the Input from the option and click on input and drag it to the input place as shown in the below picture. Double click on Input-1 and give a name to it “Start-1”, and continue for other inputs, Input-2, Input-3, as well as shown in the below pictures. Now, you have three Inputs, as Start-1, Start-2, and Start-3. Now take three more inputs, Input-4, Input-5, and Input-6 and connect them in series mode. Right click on the Input-4 and select “Normally closed” to make it NC. And do the same for other two inputs and give names to Inputs 4, 5, 6 as Close-1, 2, 3 respectively. Select an Output from the Menu and put it to Coil. That is our output. Select ‘Contact’ of output Q1 and drag i

  Ø   Opto-coupler is an electronic component that transfers electrical signals from one circuit to another circuit with isolation Ø   These are also known as Opto-isolator, photo coupler, and optical isolator     Uses Ø   Isolation between circuits Ø   It prevents damage in one circuit due to damage in another circuit Ø   Prevention of unwanted noise Ø   Both circuits can work on different voltage levels   Opto-coupler: PC 817 Ø   It has four pins Ø   Pin-1 is Anode & 2 is Cathode of the LED Ø   Pin-3 is Emitter & 4 is Collector of the Photo Transistor Ø   When light of LED falls on the Phototransistor base it conducts Ø   If there is fault in either circuit, another circuit will remain safe Ø   This is 4 pins opto-coupler component Ø   Pin-1 is Anode & 2 is Cathode of the LED Ø   Pin-3 is Emitter & 4 is Collector of the Photo Transistor Ø   Mark on top-left, shows that pin counting starts from here Ø   SMD version is also availabl

What is an MOV? Metal Oxide Varistors AKA MOVs are electronic devices designed to suppress surges in electrical and electronic circuits.   A Metal Oxide Varistor is a non-linear surge suppressor device, which is used to suppress sudden, high abnormal voltage transients or surges, especially during the power ON of a switch or natural thunder lightening situations. This is mostly used in sensitive electronic circuits to make them safe against such catastrophic occurrences. MOV is a non-polar device, which means you can connect it with any side. It is a voltage dependent device, which means this device will react to the changes in voltage conditions. Therefore, MOV is specified to trigger whenever the rated voltage magnitude across their connections is exceeded. The voltage rating at which an MOV may be defined to fire and short the transient to the ground is called its ‘clamping voltage’ . For an example, if the clamping voltage rating of an MOV is 420V then i