Browse Prior Art Database

Tube Tester

IP.com Disclosure Number: IPCOM000098541D
Original Publication Date: 1959-Feb-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 28K

Publishing Venue

IBM

Related People

Wheele, ND: AUTHOR

Abstract

The left-hand circuit is for checking 5965 tubes for excessive grid emission. A supply of 7.5 volts is provided to the filament for two minutes to cause the tube to reach operating temperature in a reasonably short time. Negative grid current indicates grid emission, and a meter reading in excess of 10 microamperes is considered cause for rejecting the tube.

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Tube Tester

The left-hand circuit is for checking 5965 tubes for excessive grid emission. A supply of 7.5 volts is provided to the filament for two minutes to cause the tube to reach operating temperature in a reasonably short time. Negative grid current indicates grid emission, and a meter reading in excess of 10 microamperes is considered cause for rejecting the tube.

The right-hand circuit checks for cathode emission in 5687, 6350 or 7044 tubes. Since a decrease in cathode emission results in a decrease in potential difference between cathode and grid, when the tube is conducting, the cathode- grid potential is used as a measure of cathode emission. A meter reading of 2.0 volts for a 5687 tube, 1.3 volts for a 6350 tube and 1.7 volts for a 7044 tube indicates that the tube under test should be rejected. A diode across the meter protects the meter movement in case a tube is removed during the test.

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