User Guide

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Common-cathode stage, unbypassed cathode:
Voltage Gain (Output 1):
Av = (mu * ra )/( ra + (mu + 1)*Rk)
Input impedance:
Rin = Rg
Output impedance (Output 1):
Rout = [( ra)/(mu + 1)] //Rk
Frequency response (Output 1):
f1 = 1/(2*pi*Ci*Rg) - highpass breakpoint due to Ci/Rg
f2 = 1/(2*pi*Co*(Rout + Rl)) - highpass breakpoint due to Co/Rout/Rl
Where:
Rg = the grid resistor
Rp = the plate resistor
Rk = the cathode resistor
Rl = the load resistance, or the input resistance of the next stage
Ra = the total load resistance, which is Rp in parallel with the input resistance of the next stage, Rl. If
there is no Rl, Ra = Rp.
ra = the internal plate resistance of the tube
mu = the mu of the tube