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Another useful characteristic is the common-base current gain, α F. The common-base current gain is approximately the gain of current from emitter to collector in the forward-active region. This ratio usually has a value close to unity; between 0.980 and 0.998. It is less than unity due to recombination of charge carriers as they cross the ...
Some models base the collector current correction factor on the collector–base voltage V CB (as described in base-width modulation) instead of the collector–emitter voltage V CE. [3] Using V CB may be more physically plausible, in agreement with the physical origin of the effect, which is a widening of the collector–base depletion layer ...
The 2N3773, with a TO-3 case has slightly lower gain but significantly higher maximum ratings (150 W, 140 V ceo, 16 amps). The 2N3054 is a much lower power version of the 2N3055, rated at 25 W, 55 V and 4 A, but became almost obsolete about the late 1980s when many TO-66 devices were withdrawn from mainstream manufacturers's lists.
The 2N3904 is an NPN transistor that can only switch one-third the current of the 2N2222 but has otherwise similar characteristics. The 2N3904 exhibits its forward gain (beta) peak at a lower current than the 2N2222, and is useful in amplifier applications with reduced I c, e.g., (gain peak at 10 mA for the 2N3904 but 150 mA for the 2N2222).
It offers high current gain (typically 200), medium input resistance and a high output resistance. The output of a common emitter amplifier is inverted; i.e. for a sine wave input signal, the output signal is 180 degrees out of phase with respect to the input.
It is a 0.6-ampere, 60-volt, 400-milliwatt transistor.Its transition frequency f T (where the current gain drops to one) under specified test conditions is 200 Megahertz.At low frequencies, the current gain (beta) is at least 100.
Figure 1: Basic NPN common collector circuit (neglecting biasing details).. In electronics, a common collector amplifier (also known as an emitter follower) is one of three basic single-stage bipolar junction transistor (BJT) amplifier topologies, typically used as a voltage buffer.
The current gain is very nearly unity as long as R S ≫ r E. An alternative analysis technique is based upon two-port networks . For example, in an application like this one where current is the output, an h-equivalent two-port is selected because it uses a current amplifier in the output port.