Electronics Coach

Definition:  The term Varistor is formed by the combination of two words Variable and Resistor. It means it is a variable resistance. The resistance of varistors varies with the applied voltage. The resistance shows nonlinear behaviour with applied voltage. The varistors protect the circuit by allowing excess current to flow through them and prevent the circuit from getting damaged.The current- voltage characteristics of varistor also possess nonlinear characteristics. You must be thinking … [Read more...] about Varistor

Definition: A backward diode is a semiconductor device which works in reversed biased mode. It is designed by providing variation in the design characteristics of Zener diode and tunnel diode. It is unilateral device because its designing mechanism allows it to operate in one direction only. It is designed for specific purpose. It works in the same way in reverse biasing as the conventional diode operates in forward biasing. The negative resistance characteristics of tunnel diode are used in … [Read more...] about Backward Diode

Definition: Point contact diode is formed by touching a metallic wire with an N-type semiconductor to form a small area of contact. This form a small point junction. It is widely used because such a small point junction possesses a small value of junction capacitance. Thus, the charge storage at the junction is low. Due to this, the switching ability of diode is much better than a conventional diode. Construction of Point Contact Diode It is formed by a contact of an N-type semiconductor … [Read more...] about Point Contact Diode

Definition:  Fast Recovery Diode is a semiconductor device which possesses short reverse recovery time for rectification purpose at high frequency. A quick recovery time is crucial for rectification of high-frequency AC signal. Diodes are mostly used in rectifiers because they possess ultra-high switching speed. The major problem with the conventional diode is that they possess quite high recovery time. Due to which the rectification of high frequency is not possible with a conventional … [Read more...] about Fast Recovery Diode

Step Recovery diode is a semiconductor device with unusual doping; it is also a voltage-dependent variable capacitor. The doping density is extremely small near junction area. Thus, the density of charge carriers is also low near the junction. Due to which charge storage is negligible near the junction, and this leads to fast switching of the diode from ON state to OFF state. It is also used as a charge controlled switch in various application due to its fast switching at low frequencies. … [Read more...] about Step Recovery Diode

Definition: LASER is an acronym of Light amplification by stimulated emission of radiation. A laser diode emits radiation of a single wavelength or sometimes a narrow band of closely spaced wavelength. It emits light due to stimulated emission, in this when an incident photon strike semiconductor atom, the electrons at higher energy level recombine with lower energy level hole. Due to this two photons are emitted one incident photon and other is emitted due to recombination of electrons and … [Read more...] about Laser Diode

Definition: Gunn diode is a transferred electronic device, which is composed of only one type of semiconductor i.e. N-type and utilizes the negative resistance characteristics to generate current at high frequencies. It is used to generate RF and microwave frequencies. It is composed of only N-type semiconductor because N-type semiconductor has electrons as majority carriers. And transferred electronic devices use such materials which have electrons as majority charge carrier. For such … [Read more...] about Gunn Diode

There are mainly two types of Photodiode i.e. PIN Photodiode and Avalanche Photodiode. PIN Photodiode Definition: PIN Photodiode is a photodetector in which the depletion layer thickness can be modified for generation of large photocurrent. If the thickness of depletion layer is more then the surface area on which light is falling also increases. Due to this, the conversion efficiency of a photodiode increases and more photocurrent will generate. Construction of PIN Photodiode The P-type … [Read more...] about Types of Photodiode

Definition: Photodiode is a two terminal electronic device which, when exposed to light the current starts flowing in the diode. It is operated in reverse biased mode only. It converts light energy into electrical energy. When the ordinary diode is reverse biased the reverse current starts increasing with reverse voltage the same can be applied to the photodiode. But in the case of photodiode the current can flow without application of reverse voltage, the P-N junction of the photodiode is … [Read more...] about Photodiode

Definition: Shockley diode is a four layer (P-N-P-N) device. It conducts when it is forward biased and stops conducting when it is reverse biased. The major difference between conventional diode and Shockley diode is, it starts conducting when the forward voltage exceeds break-over voltage.  It was invented by William Bradford Shockley, and that’s why it is named after its inventor. Shockley Diode is not widely available commercially. Still, it forms the backbone of devices like Diac, Triac, … [Read more...] about Shockley Diode