VACUTRACE Vacuum Tube Curve Tracer
10
Sweep rate is adjusted by the Rate/Offset control. Use this to reduce flicker in the
display. Setting the Triode/Pentode control to pentode enables the Screen control.
It is best to start at 100V and work your way up.
You may switch modes at any time and set controls to any position in any
combination without causing damage to VacuTrace.
Transfer Function
By switching the Output to gm the oscilloscope display changes to current vs. grid
voltage. You will probably have to readjust the attenuator on the X-axis to get a
better aspect ratio. This unusual set of curves defines the transfer function for a
given plate voltage. However, you must insure that neither the Current nor Power
limit controls are involved. Drawing imaginary lines connecting each peak yields the
input-to-output transconductance transfer function. Linearity of the tube is
demonstrated by the spacing from peak to peak.