Darlington transistor is a well known and popular connection using a pair of bipolar transistor junction transistor (BJT), designed for operating like an unified “superbeta” transistor. The following diagram shows the details of the connection. Definition A Darlington transistor can be defined as a connection between two BJTs that allows them to form a single […]
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How Varactor (Varicap) Diodes Work
A varactor diode, also called varicap, VVC (voltage-variable capacitance, or tuning diode, is a type of semiconductor diode which features a variable voltage-dependent capacitance on its p-n junction when the device is reversed biased. Reverse bias basically means when the diode is subjected to an opposite voltage, meaning a positive voltage at the cathode, and […]
Tunnel Diode – Working and Application Circuit
A tunnel diode is a type of semiconductor diode which features a negative resistance on account of a quantum mechanical effect known as tunneling. In this post I have explained the basic characteristics and working of tunnel diodes, and also a simple application circuit using this device. We will see how a tunnel diode could […]
5 Best IC 555 Oscillator Circuits Explored
In this post I have explained how to build and optimize 5 useful IC 555 oscillator circuits, whose waveforms can be further enhanced for generating complex sound effects. Overview The basic mode that is normally employed for making IC 555 oscillators is the astable circuit mode. If we look at the astable circuit shown below, […]
Understanding MOSFET Avalanche Rating, Testing and Protection
In this post I have explained MOSFET avalanche ratings, and learn how to understand this rating in the datasheet correctly, how the parameter is tested by the manufacturer, and measures to protect MOSFETs from this phenomenon. The avalanche parameter not only helps to verify the devices ruggedness, it additionally helps filtering out weaker MOSFETs or […]
Understanding MOSFET Safe Operating Area or SOA
If you are wondering or worried about precisely how much power your MOSFET can tolerate under extreme conditions, or under extreme dissipative situations, then the SOA figures of the device is exactly what you should be looking at. In this post we will be comprehensively discussing the Safe Operating Area, or the SOA, as it […]





