The base bias resistor in the figure is designed and calculated according to the formula: Rb=β(Rc+Rc//RL)

For example, Rc=RL=1k, β=100, then 1k //1k=0.5k, Rb=100x(1k+1k//1k)=100x1.5k=150k

Ib≈Ucc/Rb=9V/150k=0.06mA

rbe=2026mV/0.06mA=20433=633Ω

Voltage amplification factor |A|=β(Rc//RL)/(rs+rbe)

According to| A|=50 can calculate the required internal resistance value

rs=β(Rc//RL)/|A|-rbe=100×0.5k/50-633Ω=1000Ω-633Ω=467Ω< /p>

If the actual internal resistance of the signal source is less than 467Ω, a resistor can be connected in series outside to artificially increase the internal resistance. By adjusting the external internal resistance rs of the signal source, the voltage gain can reach 50 times.

The maximum undistorted output voltage amplitude Uommax=Ucc/(2+Rc/RL)=9V/(2+1)=3V

The maximum undistorted input voltage amplitude is the maximum signal Amplitude Uimmax=Uommax/|A|=3V/50=0.06V=60mV