# current gain in cc mode

The emitter follower configuration is mostly used as a voltage buffer. CC can’t able to provides high current gain for amplifying circuits. = It is called the common-collector configuration because (ignoring the power supply battery) both the signal source and the load share the collector lead as a common connection point as in the figure below. u Using Ohm's law various currents have been determined and these results are shown on the diagram. The common base connection for both NPN and PNP transistors is as shown in the following figure. Zout = Vout / Io. Input impendence of CC amplifier could be calculated using the equation In CE configuration, by keeping the base current IB constant, if VCE is varied, IC increases nearly to 1v of VCE and stays constant thereafter. In this article, you will be able to learn and understand the working of Common Collector Amplifier, their characteristics, and their applications. • Output is 180 degree out of phase. The CM pin provides an accurate voltage that is proportional to the output current of the buck power stage. its current gain in the cc mode is - 2901166 As we discussed in our previous article, there are three transistor configurations that are used commonly for signal amplification i.e. In the CB configuration, the input current is the emitter current IE and the output current is the collector current IC. BJT Ratings Some of the important maximum ratings of BJT are If this is the case, multiple transistors may be staged together in a popular configuration known as a Darlington pair, just an extension of the common-collector concept shown in the figure below. The approximation equation of voltage gain is given by, The overall voltage gain can be defined as, This ratio can be directly derived from the voltage gain Av, and a voltage division between the source resistance Rs and the amplifier input resistance Ri, After substitutions of appropriate equations, the overall voltage gain is given by. The voltage gain is the ratio of output voltage to input voltage. R When the emitter current flows into the base terminal and doesn’t perform as collector current. R The name itself implies that the Emitter terminal is taken as common terminal for both input and output of the transistor. With the above idea, let us try to draw some expression for collector current. Hence, the current gain in Common Emitter connection is very high. Because of that, it called a common collector( CC) transistor. Your email address will not be published. for large current gain Applying the common-collector circuit to the amplification of AC signals requires the same input “biasing” used in the common-emitter circuit: a DC voltage must be added to the AC input signal to keep the transistor in its active mode during the entire cycle. In essence, this circuit regulates the voltage across the load by keeping current through the series resistor at a high enough level to drop all the excess power source voltage across it, the Zener diode drawing more or less current as necessary to keep the voltage across itself steady. Common collector application: voltage regulator. Here for common collector circuit, the input current is base current ( IB) and output current is emitter current ( Ie). In another side, common collector( CC) transistor gives high voltage gain but low current gain. applications of common collector transistor, common collector transistor configuration, input and output characteristics of common emitter configuration, SCR characteristics and Mode of Operation, All about Transistor PDF notes & Revision – Basics of Transistor, Electromagnetic Spectrum PPT & PDF Free Download, Top 5 Best Electrical Safety PPT Presentation Free Download, Basic Electronics Components and Their Functions PPT, PDF Free Download, Electron Transport Chain PPT Free Download, Basic Electronics PPT Slides Free Download, Speed Control Of Induction Motor | Detailed Explanation, Applications of Single Phase Induction Motor, What is Ripple Factor? We already cover CE and CB configuration in a previous article here we take a detailed article on CC configuration of the transistor. (Parameter This configuration provides current gain but no voltage gain. The ratio of change in collector current (ΔIC) to the change in base current (ΔIB) is known as Base Current Amplification Factor. : <1). R As the output resistance of CE circuit is less than that of CB circuit. Moreover, a close examination reveals that the output voltage is nearly identical to the input voltage, lagging behind by about 0.7 volts. The voltage gain provided by this circuit is less than 1. The high current gain combined with near-unity voltage gain makes this circuit a great voltage buffer. e R • Power gain is upto 37 dB. Sometimes the high current gain of a single-transistor, common-collector configuration isn’t enough for a particular application. Good transistor amplifiers essentially have the following parameters high gain, high input impedance, high bandwidth, high slew rate, high linearity, high efficiency, high stability, etc. It is denoted by γ. Common emitter circuit has high input resistance and low output resistance, due to these characteristics this circuit is mostly used in impedance matching applications. Ripple factor of Half wave and full wave rectifier, Difference Between N type and P type Semiconductor | Quick Guide. For most cases, common emitter circuits are used for amplifying circuits because it provides high voltage gain as well as high current gain. β The circuit is shown below, the AC equivalent circuit to calculate the output resistance. Here emitter current Ie is shown on Y-axis. The current amplification factor is the ratio of change in emitter current ( Ie) to change in base current ( Ib ). $$I_C(1 - \alpha) = \alpha I_B + I_{CBO}$$, $$I_C = \frac{\alpha}{1 - \alpha}I_B + \frac{1}{1 - \alpha}I_{CBO}$$, The collector emitter current with base open is ICEO, $$I_{CEO} = \frac{1}{1 - \alpha}I_{CBO}$$, Substituting the value of this in the previous equation, we get, $$I_C = \frac{\alpha}{1 - \alpha}I_B + I_{CEO}$$. Unlike the common-emitter amplifier from the previous section, the common-collector produces an output voltage direct rather than inverse proportion to the rising input voltage.

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