 Uh:	heater voltage
 Ih:	heater current
 Ua:	anode voltage
 Ia:	anode current
 Usc:	screen voltage
 Isc:	screen current
 Ua2:	second anode voltage
 Ia2:	second anode current
 Ug1:	grid1 voltage
 Rg1m:	maximal grid1 resistor
 S:	mutual conductance
 Gain:	gain coefficient
 Rint:	internal resistance
 Ra:	optimal load resistance
 Pout:	output power
 Pa:	anode power
