Special Diode | Tunnel Diode | Varactor Diode | Shockley Diode

What is Tunnel Diode A tunnel diode is a pn junction that exhibits negative resistance between two values of forwardvoltage (i.e., between peak-point voltage and valley-point voltage). A conventional diode exhibits *positive resistance when it is forward biased or reverse biased. However, if a semiconductor junction diode is heavily doped with impurities, it exhibits negative … Read more

What is Photo diode | Operation | Applications | Optoisolator

What is Photo diode ? A photo diode is a reverse-biased silicon or germanium pn junction in which reverse current increases when the junction is exposed to light. The reverse current in a photo-diode is directly proportional to the intensity of light falling on its pn junction. This means that greater the intensity of light … Read more

What is LED (Light-Emitting Diode) | LED Voltage and Current

What is LED ? A light-emitting diode (LED) is a diode that gives off visible light when forward biased. Light-emitting diodes are not made from silicon or germanium but are made by using elements like gallium, phosphorus and arsenic. By varying the quantities of these elements, it is possible to produce light of different wavelengths … Read more

Voltage Stabilisation | Zener Diode

Whats is Voltage Stabilisation A rectifier with an appropriate filter serves as a good source of d.c. output. However, the majordisadvantage of such a power supply is that the output voltage changes with the variations in the input voltage or load. Thus, if the input voltage increases, the d.c. output voltage of the rectifier also … Read more

Voltage Multiplier | Half Wave Voltage Doubler

What is Voltage Multiplier ? With a diode, we can build a rectifier to produce a d.c. voltage that is nearly equal to the peak valueof input a.c. voltage. We can also use diodes and capacitors to build a circuit that will provide a d.c output that is multiple of the peak input a.c. voltage. … Read more

Filter Circuit | Types of Filter Circuits

What is Filter Circuits ? Generally, a rectifier is required to produce pure d.c. supply for using at various places in the electronic circuits. However, the output of a rectifier has pulsating *character i.e. it contains a.c. and d.c. components. The a.c. component is undesirable and must be kept away from the load. To do … Read more

Nature of Rectifier Output | Ripple Factor | Comparison of Rectifiers

Nature of Rectifier Output It has already been discussed that the output of a rectifier is pulsating d.c. as shown in Fig. 6.37. In fact, if such a waveform is carefully analyzed, it will be found that it contains a d.c. component and an a.c. component. The a.c. the component is responsible for the *pulsations … Read more

Faults in Centre Tap Full Wave Rectifier

Faults in Centre Tap Full Wave Rectifier The faults in a center tap full-wave rectifier may occur in the transformer or rectifier diodes. Fig.6.36 shows the circuit of a center-tap full-wave rectifier. A fuse is connected in the primary of the transformer for protection purposes. We can divide the rectifier faults into two classes viz. … Read more

what is Semiconductor Diode | Properties of Diode

What is Semiconductor Diode It has already been discussed in the previous article that a pn junction conducts current easily when forward biased and practically no current flows when it is reverse biased. This unilateral conduction characteristic of pn junction (i.e. semiconductor diode) is similar to that of a vacuum diode. Therefore, like a vacuum … Read more

What is PN Junction | Properties of PN Junction

What is PN junction ? When a p-type semiconductor is suitably joined to n-type semiconductors, the contact surface is called PN junction. Most semiconductor devices contain one or more PN junctions. The PN junction is of great importance because it is in effect, the control element for semiconductor devices. Thorough knowledge of the formation and … Read more