Common collector configuration physics and radioelectronics. Bjt characteristics theory the transistor is a two junction, three terminal semiconductor device which has three regions namely the emitter region, the base region, and the collector region. At first glance, this looks like an insulator but the actual behavior is far more interesting, if we apply external voltages properly n n p collector emitter base moderately doped. If v ce increases too much, the transistor goes into the breakdown region. In another side, common collector cc transistor gives high voltage gain but low current gain. Commoncollector configuration of a transistor youtube. Indium electroplated into the depressions formed the collector and emitter. The other name for the common collector is emitter follower.
Transistor emitter follower, common collector amplifier. The curve describes the changes in the values of input current with the variation in the values of input voltage keeping the output voltage constant. It is also often more convenient to use a discrete transistor for an individual circuit within a larger system, for which ics are not readily available. The power gain of the common collector amplifier is medium. Transistors characteristics for cb, ce and cc transistors. To fully describe the behavior of a transistor with cc configuration, we need two set of characteristics input characteristics and output characteristics. When the transistor saturates and collector voltage approaches emitter voltage, collector voltage goes below ground and changes polarity. The product has constant h fe characteristics in a wide current range, providing highquality audio sounds. Transistors now that we know about diodes, lets put two of them together, as follows. Common base cb transistor gives high current gain but low voltage gain. A common base and a common collector amplifier will be designed and tested.
When i b 0 a, the transistor is in its cutoff region, and only a small leakage current flows as i c. The frequency response will be measured and the dc voltages will be. These were made by etching depressions into an ntype germanium base from both sides with jets of indiumiii sulfate until it was a few tenthousandths of an inch thick. Transistors characteristics are graphs of the various currents ibis current into the base, ie is current out of the emitter, and icis current into collector and voltages. Commoncollector configuration of a transistor topics covered. Any twoport network which is analogous to transistor configuration circuits can be analysed using three types of characteristic curves. In a common emitter circuit you only have one power supply and the emitter is connected to ground, so collector voltage cannot go below ground. Description the 2sc3519 is an npn transistor of 160 v, 15 a. Figure 98 shows collector curves for different values of base current.
This is the main reason for use in a most amplifying circuit. Input characteristics of common collector circuit is a curve between input current here base current ib and input voltage here basecollector voltage vcb at constant emittercollector voltage vec. This device can also be used in power switching circuits such as relay or solenoid drivers, dc. The object is to solve for the smallsignal voltage gain, input resistance, and output resistance. By considering the transistor configuration circuits to be analogous to twoport networks, they can be analyzed using the characteristiccurves which can be of the following types. Dc solution a replace the capacitors with open circuits. A simple circuit for measuring transistor characteristics as we said, bipolar transistors have three terminals. The common collector transistor circuit configuration gains its name from the fact that the collector circuit is common to both input and output circuits, the base being associated with only the input, then the emitter with the output only. Common collector configuration of transistor detailed. Three terminals of transistor are emittere, baseb, and collector c. The first highfrequency transistor was the surfacebarrier germanium transistor developed by philco in 1953, capable of operating up to 60 mhz. Common emitter transistor configuration, characteristics. The curve obtains between the base current i b and the collector base voltage v cb at constant collector emitter voltage v ec shows the input characteristics. What is the output characteristic of the commoncollector.
Silicon npn epitaxial planar transistor 2sc3519 data sheet 2sc3519dse rev. The common collector amplifier has high input impedance and low output impedance. In ce transistor it gives high current gain and high voltage gain. The objective of this experiment is to explore the basic applications of the bipolar junction transistor bjt. Eventually,itcan help virtually to meet the moores law, guiding to a new paradigm of electronics where trancitors and transistors are combined optimally. The output characteristic of the commonbase stage is a horizontal line the first attached picture. A missing active devicetrancitor for a new paradigm of. Transistor characteristics are the plots which represent the relationships between the current and the voltages of a transistor in a particular configuration.
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