Last updated   Home

The Vacuum Tube Directory



Tube data

Tube manufacturers & suppliers

Simple Tube emission test

  • A tube with low electron emission from the cathode performs in general unsatisfactorily, especially in some critical circuits. A simple method to check emission consists in applying an AC voltage (at 50 or 60 Hz) between the cathode and all the other electrodes tied together (for example in a triode one should connect together the grid and the plate) and measuring the DC current. That gives a relative indication of the emission. An emission test must be short to avoid damaging the tube (3 seconds is the maximum recommended). This table gives the voltage and current values for a number of tubes.

Simple Tube projects

Power Tubes

Interesting Tube pages

© 2006-2013