Cathode bias resistor for class a triode

This Paper presents a useful "handbook type" equation for calculating a suitable self-bias resistor for a class A triode amplifier stage designed for maximum signal output. It is shown also that the loss in gain is six decibels, when the cathode resistor is not shunted by a by-pass capacitor. This information provides a timesaving method for determining the cathode resistor, with only a knowledge of plate resistance and transconductance, and without the necessity of a family of plate characteristic curves.