Dynamic power dissipation short circuit power switching power gliching power static power dissipation degrees of freedom supply voltage scaling approaches. Emitter, collector and base in its essence, a transistor consists of two diodes arranged back to back. Power amplifiers introduction to power amplifiers power amplifiers amplifier circuits form the basis of most electronic systems, many of which need to produce high power to drive some output device. Bipolar junction transistors bjt general configuration and definitions the transistor is the main building block element of electronics.
The rc coupled amplifier, introduction to power amplifiers, transistor as switch. It is the technology that is behind the concept of power converters, power inverters, motor drives, switching power supplies etc. The configuration shown above is called an npn transistor. In a transistor a very small current input signal flowing emitter tobase is able to control a much larger current which flows from the system power. Power electronics signifies the word power electronics and control or we can say the electronic that deal with power equipment for power control.
Mos transistor qualitative description assume an nchannel receives its name from the type of channel present when current is flowing device with its source and substrate grounded i. Chitralekha mahanta, department of electronics and communication engineering,iit guwahati. Modeling and simulation, hvdc transmission, ac transmission applications, reactive compensation for power flow control, shunt compensation, control and harmonic interactions, distribution applications, power and voltage quality, static series compensators for voltage sag correction, fault current limiters. This was a type of electrical rectifier that was used for converting high alternating. Flow of current from source to drain is controlled by the gate voltage. Module 2 lecture 3 biasing the bjt nptel basic electronics. A transistor acts as a good amplifier in this linear region. In the transistor, every three regions emitter, base, and emitter has a different width in the transistor. Electronic materials, devices, and fabrication by prof s. If the transistor is a pnp, then the arrow points to the base of the transistor, otherwise it points to the output. Nptel video lectures, nptel online courses, youtube iit videos nptel courses. If this load line is drawn only when dc biasing is given to the transistor, but no input signal is applied, then such a load line is called as dc load line. All voltages are shown in their positive direction.
An npn negativepositivenegative type and a pnp positivenegativepositive type the most commonly used transistor configuration is the npn transistor. Each has differnet characteristics, and by designing the circuit around one of these configurations it is possible to achieve the characteristics required. Emitter is heavily doped, collector is moderately doped and base is lightly doped and base is very thin. Lecture notes on power electronics veer surendra sai. The transistor is a three terminal device which offers current gain. Can control largepower circuit with smallpower input 2. Bipolar junction transistors emitter p n collector base pnp transistor emitter n p base npn transistor bipolar. Power amplifiers purpose of a power amplifier generate high output power efficient conversion of dc power to rf power linear amplification generally pas will be common source cascode inductor is a choke to provide d apacitor is a ac coupling path to output james buckwalter 2.
Control by the gate voltage is achieved by modulating the conductivity of the semiconductor region just below the gate. A mosfet is by far the most common transistor in digital circuits, as hundreds of thousands or millions of them may be included in a memory chip or microprocessor. This led to the development of the power metal oxide semiconductor field effect transistor mosfet. Jan 17, 2017 56 videos play all basic electronics nptel arsh sharma the evolution of computing vacuum tube to transistor to integrated circuit documentary duration. Symbols and nomenclature of a a npn and b pnp transistor.
In a class a amplifier, the transistor conducts for the full cycle of the input signal 360 used in lowpower applications the transistor is operated in the active region, between saturation and cutoff the load line is drawn on the collector curves between saturation and cutoff. Capacitively coupled multistage transistor amplifier s bharadwaj reddy august 17, 2016 september 27, 2016 two or more amplifiers can be connected in a cascaded arrangement with the output of one amplifier driving the input of the next. There are three configurations that cna be used for a transistor. The base region is much thinner than the either the collector or emitter regions. This signifies its an npn transistor current flows in the direction of the arrow. The course introduces basics of power electronic devices and converters. Constructional features, operating principle, characteristics and. We also learnt that the junctions of the bipolar transistor can be biased in one of three different ways common base, common emitter. Module 2 lecture 3 biasing the bjt lecture series on basic electronics by dr. Power mosfets application note an850 power mosfet basics. Bipolar junction transistor bjt npntransistor pnptransistor bjt is a 3 terminal device.
Today power electronic uses components like diodes, gtos and transistors etc. The symbol of the transistor has an arrow on the emitter. Audio amplifier output power may be anything from less than 1 watt to several hundred watts. A typical switching circuit using a pnp transistor is shown at the left. Parasuraman,department of metallurgy and material science,iit madras. Ajit pal, computer science and engineering, iit kharagpur. The word transistor is a combination of the two words trans fer var istor which describes their mode of operation way back in their early days of electronics development.
Nptel provides elearning through online web and video courses various streams. The collector is moderately doped and the emitter is heavily doped. A diodes iv characteristic is shown in figure 6 below. Lecture 24 mosfet basics understanding with no math. Base collector emitter q1 2n3904 a transistor is basically a current amplifier. You can always remember that the arrow points at the n material. The power mosfet is used in applications such as switched mode power supplies. Can isolate different regions of complex circuits i. Schlecht, laser diode driver based on power converter technology, ieee transactions on power electronics, vol. Main power source ref signal circuit power electronics based on the switching of power semiconductor devices. The bipolar power transistor is a three layer npn or pnp device within the working range, the collector current ic is a function of the base current ib, a change in the base current giving a corresponding amplified change in the collector current for a given collector emitter voltage vce. The ratio of these two currents is of the order of 15 to 100.
The first high power electronic device was mercuryarc valves. We will explore the commonsource and commongate configurations, as well as a cs amplifier with an active load and biasing. The ratio of these two currents is of the order of 15 to. The most common type is an acdc converter that is used in most of our daily electronic devices like computers, battery chargers, and television set etc. There are two basic types of bipolar transistor construction, pnp and npn, which basically describes the physical arrangement of the ptype and ntype semiconductor materials from which they are. The load line is drawn by joining the saturation and cut off points. Nptel video lectures, iit video lectures online, nptel youtube lectures, free video lectures, nptel online courses, youtube iit videos nptel courses. The igfet or mosfet is a voltage controlled field effect transistor that differs from a jfet in that it has a metal oxide gate electrode which is electrically insulated from the main semiconductor nchannel or pchannel by a very thin layer of insulating material usually silicon dioxide, commonly known as glass.
The region that lies between these two is the linear region. Natarajan, department of physics, iit madras for more courses visit. Collector npn transistor pnp transistor p n p n p n. Transistor amplifiers transistor has 3 legs, one of them is usually grounded. Chitralekha mahanta, department of electronics and communication engineering. In the previous tutorial we saw that the standard bipolar transistor or bjt, comes in two basic forms. Methods of transistor biasing s bharadwaj reddy august 14, 2016 september 27, 2016 in the interest of simplicity and economy, it is desirable that transistor circuit should have a single source of supplythe one in the output circuit i. Other transistors have characteristics that are qualitatively similar to those of the bjt although the physics of operation may. This is especially true in high frequency circuits where the power mosfet is particularly valuable due to its inherently high switching speed. Since they can be made with either ptype or ntype semiconductors, complementary pairs of mos transistors can be used to make switching circuits with very low power consumption, in.
Transistor has three terminals emitter, base, and collector. Transistor basics emitter to base junction is forward biased normally collector to base junction is reverse biased normally transistors are current operated devices, so kcl should be applied first. Npn transistor tutorial the bipolar npn transistor. Electronics nptel online videos, courses iit video lectures. It is a semiconductor device and it comes in two general types. The principle of operation of the two transistor types. When transistors are used in digital circuits they usually operate in the. Verilog coding, metal oxide seminconductor field effect transistor mosfet, fabrication process and layout design rules, propagation delays in mos, power disipation in cmos circuits, semiconductor memories. The terminal on the left is called the emitter, the terminal on the right is.
Controlling the flow of electrical energy by switching electronic circuits is what power electronics is all about. Introduction to power electronics ecen 47975797 robert w. Transistor basics a bipolar junction transistor is a three layer npn or pnp semiconductor device. Mosfet basics summary the bipolar power transistor bpt, as a switching device for power applications, had a few disadvantages. The collector region is usually thicker than the emitter as the largest. Lecture 24 mosfet basics understanding with no math reading. Power electronics nptel online videos, courses iit video. Here we will describe the system characteristics of the bjt. The transistor is a three semiconductor current controlled device. Piv is the peakinversevoltage of the diode forward bias occurs when the ptype block is connected to the positive terminal of the battery and the ntype is connected to the negative terminal of the battery, as shown below. Mos transistor structure and device modeling mos inverters mos combinational circuits different logic families sources of power dissipation.
Power electronics introduction to power electronics 10 driver, issued may 9, 2000 4. With the development of power semiconductor technology, the power handling capabilities and. In power electronics a substantial amount of electronic energy is processed. The transistor is a semiconductor device than can function as a signal amplifier or as a solid state switch. Table of contents prelab preparation 2 before coming to the lab 2 parts list 2.
The two resistor npn and two resistor pnp drive i am going to rewrite in this. Mos amplifier basics overview this lab will explore the design and operation of basic singletransistor mos amplifiers at midband. Electronics nptel online videos, courses iit video. The three layers are called the emitter, base and collector. Bipolar transistors are current regulating devices that control the amount of current flowing through them in proportion to the amount of biasing voltage applied to their base terminal acting like a currentcontrolled switch.
927 450 1217 559 1327 875 924 224 431 37 346 418 189 1116 1386 1117 290 1086 874 1273 733 544 528 884 267 1174 1087 1329 246 71 1345 1222 521 813 300 1452 429 1429 135 236 64 111 60 136 1150 486 1213 1382 1444