The tube - endplug resistance is evaluated measuring the voltage drop across the
left endplug - tube - right endplug contacts, screwing on the two enplugs the wire
connections to a Keithley 2000 multimeter, with 0.1 mV sensitivity.
The circuit is supplied with a constant 5 mA current, monitored with a Fluke 8840A
multimeter.
The sketch of the measurement setup is shown here (pdf).

 

Some pictures of tubes after ageing:

Protvino	MPI	Cosenza
Seattle	Michigan	Michigan

 

 
 

Data

Last update 19 April 2000
Maintained by A.L.