Audio: 2 stages Transformer Audio PA
ar/21 2016
these days, i built several simple receiver with transformer Audio PA. cascade and impedance match problem is interesting.
Audio Amplifier: PA
Audio Amplifier: PA
test condition, 4:1 transformer, 450 ohm earphone
0.6v/20mV = 600/20=30 @690HZ
0.8v/20mV = 40@1.8khz
120mV output with 20 mV input, voltage gain 6 @690HZ
input impedance 1.2k
cascaded with a pre-amplifier:
4:1 transformer, use 64 ohm earphone:
LTspice simulation with NPN transistor
LTspice simulation with NPN transistor
i don't have any LTspice mode same as the transistor i used, so just pick 2SC9018, a low beta but high Ft transistor for the simulation, and it's NPN.