BJT Transistor Amplifier

Common Emitter amplifier that amplifies a signal by gain of A_v while applying a phase shift of 180 degrees to the signal. This amplifier is to be connected to a circuit driving a speaker. Emitter current is biased at 2.5mA w/ R_e resistor for improved current stability over beta and temperature variations. Tune potentiometer to vary A_v (gain). Close and re-run transient plot each time potentiometer is changed so that measured signals are re-centred at 0V DC. In this setup, maximum output range occurs when A_v <= 2.28 (R_pot <= 779ohm). This means input signal can have an amplitude as large as 850mV without distorting (in theory). Specs: -> Max gain on Amplifier (to keep BJT in active mode): A_v = 4.57 (R_pot = 1.56kohm) - The max gain you can apply to your input signal without distorting it will now depend on the amplitude of the input signal itself. -> Range of input signal (w/o distorting signal): - This depends on what you set the gain to. - The following calculations will tell you the max amplitude your input signal can be based on what you set A_v (technically R_pot) to. Calculations: -> A_v = 0.0029278*R_pot [V/V] -> Input Ampl. < (3.875 - (2.5mA)(R_pot)) / A_v OR Input Ampl. <= 850mV Use whichever is smaller.

published 1 year ago