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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 ...
The BC548 is available in three different gain groups:. "A" indicates low gain (110 to 220, typically 180) at 2 mA collector current, "B" indicates medium gain (200 to 450) "C" indicates high gain (420 to 800) So a BC548 might have a current gain anywhere between 110 and 800, but the gain of a BC548A would be within the range of 110 to 220.
In other words, the circuit has current gain (which depends largely on the h FE of the transistor) instead of voltage gain. A small change to the input current results in much larger change in the output current supplied to the output load. One aspect of buffer action is transformation of impedances.
The current gain is unity, so the same current is delivered to the output load R L, producing by Ohm's law an output voltage v out = v Thév R L / R S, that is, the first form of the voltage gain above. In the second case R S << 1/g m and the Thévenin representation of the source is useful, producing the second form for the gain, typical of ...
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).
In electronics, a common-emitter amplifier is one of three basic single-stage bipolar-junction-transistor (BJT) amplifier topologies, typically used as a voltage amplifier. It offers high current gain (typically 200), medium input resistance and a high output resistance.
All types have a maximum collector current of 100 mA, except that the original Philips tentative data dated 4.4.1966 specified a maximum collector current of 100 mA peak (I CM) for the BC107/8/9, and Telefunken originally specified a maximum collector current of 50 mA for the BC109, but since at least 1973 all have revised collector currents of 100 mA average or 200 mA peak, except that the ...
The common-emitter current gain, ... Bipolar junction transistor; Gummel–Poon model; References This page was last edited on 3 January 2024, at 22:34 (UTC ...