What is a Junction Field Effect Transistor? A JFET is a semiconductor with 3 terminals, available either in N-channel or P-channel types. It is unipolar but has similar characteristics as of its Bipolar cousins. Instead of PN junctions, a JFET uses an N-type or P-type semiconductor material between the collector and emitter (Source & Drain). […]
As already mentioned in Field Effect Transistors (FET) , JFET’s are of two types, namely N-channel JFETs and P-channel JFETs. Generally N-channel JFETs are more preferred than P-channel. N-channel and P-channel JFETs are shown in the figures below. Basic Construction. The structure is quite simple. In an N-channel JFET an N-type silicon bar, referred to
Series Inductor Filter. In this arrangeÂment a high value inductor or choke L is connected in series with the rectifier element and the load, as illustrated in figure. The filtering action of an inductor filter deÂpends upon its property of opposing any change in the current flowing through it. When the output
The drawbacks of pi-filters are the comparatively larger cost, more weight, bigger size and external field developed by the series inductor. However, these drawbacks can be overcome by replacing the series inductor by a series resistor R. Such a circuit is called the R-C filter circuit and is given in figure. By deliberate design R
Introduction to FET-Field Effect Transistor So far we have discussed the circuit applications of ordinary transistors, in which both holes and electrons take part. This is the reason that these are sometimes called the bipolar transistors. Such transistors have two main drawbacks namely low input impedance because of forward biased emitter junction and considerable noise
A simple series inductor reduces both the peakand effective values of the output current and output voltage. On the other hand a simple shunt capacitor filter reduces the ripple voltage but increases the diode current. The diode may get damaged due to large current and at the same time it causes greater heating of supply
Shunt Capacitor Filter and types of it: This is the most simple form of the filter circuit and in this arrangement a high value capacitor C is placed directly across the output terminals, as shown in figure. During the conduction period it gets charged and stores up energy to it during non-conduction period. Through this process,
We have learnt in rectifier circuits about converting a sinusoidal ac voltage into its corresponding pulsating dc. Apart from the dc component, this pulsating dc voltage will have unwanted ac components like the components of its supply frequency along with its harmonics (together called ripples). These ripples will be the highest for a single-phase half
Polyphase rectifier In polyphase rectifier we will be discussing in detail the working, the input and the output wave forms of a three phase half wave rectifier and three phase full wave rectifier, along with the connections of an interface transformer on a 6-diode rectifier. Three phase Half Wave Rectifier A three phase half wave
A Full-wave rectifier is a circuit arrangement that makes use of both half cycles of input alternating current (AC) and converts them to direct current (DC). In our tutorial on Half-wave rectifiers, we have seen that a half-wave rectifier makes use of only one-half cycle of the input alternating current. Thus a full-wave rectifier is
Centre-Tap Full Wave Rectifier We have already discussed the Full Wave Bridge Rectifier, which uses four diodes, arranged as a bridge, to convert the input alternating current (AC) in both half cycles to direct current (DC). In the case of centre-tap full wave rectifier, only two diodes are used, and are connected to the opposite
A simple Half Wave Rectifier is nothing more than a single pn junction diode connected in series to the load resistor. As you know a diode is to electric current like a one-way valve is to water, it allows electric current to flow in only one direction. This property of the diode is very useful
In this article, we are going to learn a little deep about break down characteristics of PN Junction Diode and how “reverse break down” characteristics is put into practical applications. Before getting into the details, lets have a walk through our previous articles. 1. Understanding the PN Junction – is a great article to begin
This blog post is continuation to the original post: Fabrication techniques of a P-N junction diode 1. Grown Junction Diode: Diodes of this type are formed during the crystal pulling process. P and N-type impurities can be alternately added to the molten semiconductor material in the crucible, which results in a P-N junction, as shown
General Introduction to Fabrication techniques of a P-N junction diode: In practice, the P-N junction is formed from a single mono crystalline structure by adding carefully controlled amounts of donor and acceptor impurities. Here discussion is limited only to acquaintation with the basic techniques and terminology (not expertise in fabrication). The first and foremost requirement is
Photo-diode is a two-terminal semiconductor P-N junction device and is designed to operate with reverse bias. The basic biasing arrangement, construction and symbols for the device are given in figure. It is either mounted in translucent case or has its semiconductor junction mounted beneath an optical lens. The output voltÂage is taken from across a
Class D power amplifier. Class D power amplifier is a type of audio amplifier were the power handling devices are operated as binary switches. Since the power handling devices (MOSFETS) works as perfect binary switches, no time is wasted in between the transition of stages and no power is wasted in the zero input condition.
Class C power amplifier. Class C power amplifier is a type of amplifier where the active element (transistor) conduct for less than one half cycle of the input signal. Less than one half cycle means the conduction angle is less than 180° and its typical value is 80° to 120°. The reduced conduction angle improves
In class AB power amplifiers, the biasing circuit is so adjusted that the operating point Q lies near the cut-off voltage. During a small portion of negative half cycle and for complete positive half cycle of the signal, the input circuit remains forward biased–and hence collector current flows. But during a small portion (less
Harmonic distortion in power amplifiers. Distortion is a serious problem faced in power amplifier design. In faithful amplification the output signal must be a scaled replica of the input signal and if there is any dissimilarity between the input and output waveform, then the output is said to be distorted. Unpleasant sound output coming from
Class B power amplifier. Class B amplifier is a type of power amplifier where the active device (transistor) conducts only for one half cycle of the input signal. That means the conduction angle is 180° for a Class B amplifier. Since the active device is switched off for half the input cycle, the active device
TRANSFORMER-COUPLED CLASS A POWER AMPLIFIER This is also sometimes referred to as single ended power amplifier. The term “single ended” (denoting only one transistor) is used to distinguish it from the push-pull amplifier using two transistors. In case of a direct-coupled class A power amplifier shown, the quiescent current flows through the collector resistive load
Class A power amplifier. Class A power amplifier is a type of power amplifier where the output transistor is ON full time and the output current flows for the entire cycle of the input wave form. Class A power amplifier is the simplest of all power amplifier configurations. They have high fidelity and are totally
Practical power amplifier. Audio power amplifier is an amplifier which produces amplification of power between the input and output. Theoretically every audio amplifier produces some amount of power amplification, but in practical scenario every audio amplifier cannot be called a power amplifier. It is the amount of power amplification that makes an amplifier power amplifier
Introduction Optoelectronics is the branch of electronics that combines optics and electronics. The devices that deal with this technology is called optoelectronics devices. Optoeletronic devices can be divided into two – light sensitive devices and light generating devices. We have already discussed a good amount of optoelectronic devices in our site. You can get the
