In a triac phase control circuit, the triac is triggered ON only for specific portions of the AC half cycles, causing the load to operate only for that period of the AC waveform. This results in a controlled supply of power to the load. Triacs are popularly used as a solid-state replacement of relay for […]
Electronics Theory
How Contactless Infrared Thermometers Work – How to Make One
In this post I have explained the basic working concept of thermal scanners or contactless IR thermometers, and also learn how to make a practical DIY prototype of the unit without Arduino. In the post COVID-19 era, witnessing doctors holding a contactless temperature gun and pointing toward the forehead of a COVID-19 suspect is a […]
How RC Circuits Work
In an RC circuit, a combination or R (resistor) and C (capacitor) is used in specific configurations in order to regulate the flow of current, for implementing a desired condition. One of the main uses of a capacitor is in the form of a coupling unit which allows AC to pass but blocks DC. In […]
Diac – Working and Application Circuits
The diac is a two-terminal device having a combination of parallel-inverse semiconductor layers, which allows the device to be triggered through both directions regardless of the supply polarity. Diac Characteristics The characteristics of a typical diac can be seen in the following Figure, which distinctly reveals the presence of a breakover voltage in across both […]
Unijunction Transistor (UJT) – Comprehensive Tutorial
A unijunction transistor is a 3 terminal semiconductor device which is unlike a BJT has only a single pn junction. It is basically designed to be used as a single-stage oscillator circuit for generating pulsed signals suitable for digital-circuit applications. UJT Relaxation Oscillator Circuit The unijunction transistor could be typically wired in the form of […]
Solid State Relay (SSR) Circuit using MOSFETs
SSR or Solid state relays are high power electrical switches that work without involving mechanical contacts, instead they use solid state semiconductors like MOSFETs for switching an electrical load. SSRs can be used for operating high power loads, through a small input trigger voltage with negligible current. These devices can be used for operating high […]