A Varistor is a voltage-dependent, non-linear resistor whose resistance changes significantly with applied voltage. The term varistor is derived from “variable resistor”, but unlike potentiometers or rheostats, its resistance varies automatically with voltage, not mechanically. Varistors are primarily used for over-voltage protection. Under normal operating voltage, a varistor behaves like a very high resistance device. […]
A surge protector is an electronic protection device designed to safeguard electrical and electronic equipment from voltage surges (transient overvoltage). A voltage surge is a sudden and short-duration spike in voltage that exceeds the normal operating voltage of a system. These surges may last from a few nanoseconds to milliseconds but can reach several kilovolts […]
Understanding the difference between Surge Protection and Over Voltage Protection is essential for designing robust electronic systems, selecting the right protective components, and complying with safety and EMC standards. Modern electronic and electrical systems are increasingly sensitive to abnormal voltage conditions. With the widespread use of microcontrollers, SMPS power supplies, communication modules, and semiconductor devices, […]
Electromechanical relay (EMR) is one of the oldest and still most widely used switching devices in electronics and electrical engineering. A relay is an electromechanical switching component that uses an electromagnet to mechanically operate a set of contacts. In simple words, a relay uses a small control signal (low power side) to switch large loads […]
A Solid-State Relay (SSR) is an electronic switching device that performs the same function as an electromechanical relay (EMR) but without any moving parts. Instead of mechanical contacts, it uses semiconductor devices such as thyristors, Triacs, MOSFETs, or transistors to switch electrical loads ON or OFF. Because there are no moving parts, SSRs offer longer […]
In modern electronics, signal isolation between different parts of a circuit is crucial for protection, noise reduction, and system stability. Optocouplers, also known as optoisolators, play a vital role in achieving this electrical isolation while allowing signal transmission. This article provides a thorough exploration of optocouplers (Optoisolator / Photocoupler), including their construction, working principles, advantages, […]