Kemper apower amp class
This is achieved by biasing the base of the transistor with the help of R1 and R2 resistors. The purpose of this amplifier is to amplify the AC input that is fed to it. The primary or the most important component here is the NPN transistor. Two types of input are given to this amplifier, of which one is the AC Input signal while the other one is DC input signal. Shown in the figure above is a CE, Common Emitter Amplifier. On doing that we are actually making it easier to calculate Voltage gain and input impedance later. Things become easy when while analysing a Common-Emitter amplifier, the emitter diode is treated as a small resistance. R(e)’ is the AC resistance of the transistor’s emitter diode (the most important stuff here) R(C) and R(E) are Collector and Emitter resistances respectively. In the figure above (C ), (B) and (E) are Collector, Base and Emitter terminals respectively. The Emitter-Base junction of a transistor which is forward biased actually works as a DIODE and offers a small AC resistance to the input signal. This amplification action of a transistor is fully utilized in a class A amplifier. Thus a small input at base gets amplified as a large output at Collector-Emitter. The flow of I(C) causes the difference in voltage between Collector and Emitter terminals to change which ultimately changes the component V(CE).
Transistor’s Amplifier ActionĪs shown in the above figure a small change in V(BE) causes a change in I(B) which then lifts both pink and blue gates.Īs the pink and blue gates get lifted it directly causes a large change in the collector current I(C). As this larger gate opens it allows the large current I(C) to flow from collector to emitter terminal.Īs shown above the base current I(B) and I(C) combine to form emitter current I(E) which ultimately passes to the emitter terminal. The black arrow on the left of the green Emitter terminal indicates that it’s an NPN transistor type.Īs shown above a small minute current, I(B) at the base terminal causes the small pink gate to open up which in turn causes the large blue gate to open up. The V(CE) is the difference in voltage between Collector and Emitter terminals while V(BE) is the difference in voltage between Base and Emitter terminals. So basically a small gate at base can lift up a large gate at collector. There is a big blue gate near the collector terminal which opens up automatically when we open the small pink gate present near the base terminal. The base terminal is shown as a big red B, while the collector and emitter terminals are shown as big blue C and big green E respectively. On the top left we have three types of currents I(B), shown in red, I(C), shown in blue and I(E), shown in green. The above diagram shows the different components that are present inside and outside an NPN transistor.