The three different configurations of bjt are listed below. What is common collector connection or cc configuration. Common collector configuration physics and radioelectronics. For any value of v ce above knee voltage, i c is approximately equal to. What is the emitter follower and what characteristic parameters it has. The current gain for the three transistor configurations cb, ce, and cc are alpha a, beta b, and gamma g, respectively. Ce common emitter cc common collector emitter follower cb common base the most commonly used configuration the transistor. Transistor circuits use one of three transistor configurations. The commonemitter ce, commonbase cb, and commoncollector cc configurations, their hybrid models and their terminal voltampere equations are.
It is transistor circuit in which base is kept common to the input and output circuits. Then to summarise, this type of bipolar transistor configuration has a greater input impedance, current and power gain than that of the common base configuration but its voltage gain is much lower. Cb and ce refer to how the transistor is used in a circuit. The cb configuration having a low input and high output impedance and a current gain less than 1, the voltage gain can be quite large, r o in m. Output characteristics curves of a typical bipolar transistor. What are the applications of cb, ce and cc configurations. This configuration provides current gain but no voltage gain. The emitter follower configuration is very useful for impedance matching applications because of the very high input impedance, in the region of hundreds of thousands of ohms while having a relatively low output impedance. The ce fixedbias configuration can have a significant voltage gain characteristic, although its input impedance can be relatively low. Common emitter characteristics input characteristics output characteristics.
Like the output characteristics of common base transistor ce mode has also three regions named i. As we know transistor is solid state equivalent of a triode valve. At the output, signal must remain sinusoidal in waveform. Ce, cc,cb configurations,configurations of bjt,common emitter configuration,common base configuration,common collector configuration,common emitter current g. In this type of configuration collector is common terminal between other both emitter and base terminals. Very lowless than 100 ohm lowless than 1k very high750k output dynamic resistance.
Output characteristics for ce mode is the curve or graph between collector current i c and collectoremitter voltage v ce when the base current i b is the parameter. Easily convert able from one configuration to other. The common part refers to the fact that this is the reference or ground for bo. So, lets go to know the comparison between cb, cc, and ce configuration and their characteristics, applications. The low input impedance of the common base amplifier will limit its. The voltage gain provided by this circuit is less than 1. Npn transistor circuit working, characteristics, applications. Let us compare the characteristic details of cb, ce, and cc.
Oct 05, 2011 if you need to amplify the current output from a sensor, cb is useful. Experiment 1, plotting common emitter characteristic curves. Compare bjt amplifier in ce, cb, cc configurations. Basic electronics transistor configurations tutorialspoint. Determination of the transistor parameters current amplification factor. The voltage gain for this configuration of circuit is given below. The transistor characteristic under common collector configuration is as follows. To study and draw the characteristics of fet in common source configuration. It may be noted that in cc configuration of figure 3b, b and c are the input terminals while e and c are the output terminals. Common emitter ce configuration or common emitter amplifier. Common emitter connection or ce configuration input. Jan 23, 2015 the commonemitter amplifier circuit is mostly used configuration than other bjt configurations because of its high input impedance and low output impedance and also this configuration amplifier provides high voltage gain and power gain. The common base configuration is less common as an amplifier than compared to the more popular common emitter, ce or common collector, cc configurations but is still used due to its unique inputoutput characteristics. Ce is for medium input resistance and amplification with phase reversal.
The voltagedivider bias configuration has a higher stability than the fixedbias configuration. It has high output impedance on the order of 1 to 10 mega ohms. The input characteristic of the common collector configuration is drawn between collector base voltage v ce and base current i b at constant emitter current voltage v ce. It has low input impedance on the order of 50 to 500 ohms. Similar equations using cb and cc hparameters may be written respectively for cb and cc models. The value of the output voltage v ce changes with respect to the input voltage v bc and i b with the. Common emitter amplifier a common emitter amplifier is typically used as a voltage amplifier input is applied to base,output is taken across collector and the emitter is grounded. Jul, 2015 for example, for ce configuration and hold, and also for cc and hold. Working of transistor bjt practically the working of a transistor is very simple, it can be used as a.
However, its essential voltage gain is very low cc configuration where requirement of high input. Different configurations of transistors common base. It is the curve between collector current icand collectoremitter voltage at constant base current ib. Exact comparison between cb, cc, ce configuration of bjt. The ce configuration is the only configuration which provides both voltage gain as well as current gain greater than. The behavior of these three different configurations of transistors with respect to gain is given below. They can be determined from the transistor static characteristics curves. These three transistor configurations have their own characteristics, advantages, and applications. The low input impedance of the common base amplifier will limit its use to specialized rf applications. Transistor as an amplifier in ce configuration, dc load line, concept of power gain. Vb i b i c i e vout as with ce bias design, stable op. Ce common emitter cc common collector emitter follower cb common base the most commonly used configuration the transistor is in when used as an amplifier is the common emitter. In the cc, the input is applied to the base, the output is taken from the emitter, and the.
Common collector transistor configuration cc the common collector transistor configuration is also known as the emitter follower because the emitter voltage of this transistor follows the base terminal of the transistor. Why ce configuration is preferred for amplification. Common basecb mode characteristics of bipolar junction. Before knowing about the bipolar junction transistor characteristics, we have to know about the modes of operation for this type of transistors. The sum of collector current and base current equals emitter current. Common emitter transistor configuration, characteristics. The current gain for this configuration is always greater than unity usually the typical value is about 50. The three different transistor circuit configurations are. So, lets go to know the comparison between cb, cc, and ce configuration and thei. They are convenient to use in circuit analysis and design. The most important characteristic of the bjt is the plot of the collector current, ic, versus the collectoremitter voltage, vce, for various values of the base current, ib as shown on the circuit of figure 6.
The third and final transistor configuration is the common collector configuration, shown in the below figure with the proper current directions and voltage. Cb low about 100 ce medium 800 to few k cc high about 750k output resistance input current output current input voltage applied between op voltage taken between current gain voltage gain power gain. Common base cb common emitter, ce common collector, cc input dynamic resistance. The cascode amplifier is a multistage configuration of a cc cb b ce cb c cb cc d ce cc gate 2005. Common emitter bjt circuit for determining output characteristics. This type of configuration has high resistance gain i. Emitter follower biasing typical design split bias voltage drops about equally across the transistor v ce or v cb. Output resistance of cb is the resistor connected in collector. The approximate current gain is given by simply beta, and the output impedance is normally assumed to be rc.
In cc configuration, the input resistance is high and the output resistance is low. Both have high input impedance and low output impedance. Transistor configuration common base configuration. In cb and ce configurations, input characteristics are based on the forward bias characteristics of a diode, but in cc it is different. This configuration provides good current gain and voltage gain. Current gain in ce is ratio of output current i c to the input current i b, which is represented by. This page compares cb vs ce vs cc transistor configurations and mention difference between cb, ce, cc transistor modes. Vce v i c i b ma ma vbe v 512011 2 transistor characteristics. These modes are used in various transistor based applications as per characteristics mentioned below. In cb configuration, the output v i characteristics of the transistor are drawn by taking a v cb vs. Summarizes hparameters for all three configurations. These three types of configurations respond differently to the input signal applied to the circuit because of the static characteristics of the bjt. Aug 04, 2017 ac characteristics 4 young won lim 08042017 ce amplifier.
Cb, ce, cc configuration input and output characteristics three types of configuration is available 1 common base cb configuration 2 common emitter ce configuration 3 common collector cc configuration. Common base bjt amplifier common collector bjt amplifier. Cb low about 100 ce medium 800 to few k cc high about 750k output resistance input current output current input voltage applied between op voltage taken between current. Transistors characteristics for cb, ce and cc transistors. The input characteristics describe the relationship between input current or base current i. Keeping v ce constant, with a small increase in v be the base current i b increases rapidly than in cb configurations. Equations 5 and 6 are valid for ce model of figure 2. We will assume a sinusoidal signal at the input of the amplifier. For each of the three configurations, application of kirchhoff. Generally there are three different configurations of transistors and they are common base cb configuration, common collector cc configuration and common emitter ce configuration. This transistor configuration has high output impedance and low input impedance. If cc configuration is considered for amplification, though cc amplifier has better input impedance and lower output impedance than ce amplifier, the voltage gain of cc is very less which limits its applications to impedance matching only. Ce, cc, cb configurations configurations of bjt electronic. Then, choosespecified i e, and the rest of the design follows.
The cc is also referred to as an emitterfollower and is equivalent to the electrontube cathode follower. To fully describe the behavior of a transistor with cc configuration, we need two set of characteristics input characteristics and output characteristics. The three parts of a bjt are collector, emitter and base. Can anybody explain why the input characteristics of cc. The transistor configuration comparison chart gives a rundown of the different properties of the three configurations. Plot each set of points for a given base current at one time. If source resistance of your source is much smaller than say 10 ohm, cb can be used. The basic circuit of hybrid model is same for all three configurations, only parameters are different. Transistor configuration common base, collector and emitter. Commonbase configuration cb the cb configuration having a. Cb, ce, cc configuration input and output characteristics.
The transistor is said to be in quiescent state when a it is unbiased b no current flows through it c no signal is applied to the input d emitter junction is just biased equal to collector junction 4. There isnt necessarily a difference in the transistor. In this configuration, we use base as common terminal for both input and output. Transistor circuit configurations electronics notes. In ce configuration, the collector terminal of the transistor will be connected common between the output and the input terminals. The following formula is used to calculate the current gain of the ce. We already cover ce and cb configuration in a previous article here we take a detailed article on cc configuration of the transistor. What is the difference between a cb and a ce configuration. The output characteristics of ce configuration consists of three regions which are active region, saturation region and cutoff egion. The common collector configuration, also typically known as emitter follower. Common collector configuration of transistor detailed. The input characteristics describe the relationship between input current or base current i b and input voltage or basecollector voltage v bc. To study the characteristics of transistor in common base configuration.
The value of the output voltage v ce changes with respect to the input voltage v bc and i b with the help of these values, input characteristic curve is drawn. Input characteristics output characteristics it is the curve between base. Ce, cc, cb amps parameters problems estimate voltage gain and effective voltage gain for given diagram of bjt ce amplifier known parameters. Ce configuration, common base or cb configuration, and common collector or cc configuration. Emitter follower biasing typical design split bias voltage drops about equally across the transistor v ce or v cb and v re or v b. Figure 2 below shows the input characteristics of a cb configuration circuit which describes the variation of emitter current, ie with baseemitter.
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