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Browse Prior Art Database

Beam Current Measurement

IP.com Disclosure Number: IPCOM000041419D
Original Publication Date: 1984-Jan-01
Included in the Prior Art Database: 2005-Feb-02

Publishing Venue

IBM

Related People

Authors:
O'Rourke, R van den Oever, WE [+details]

Abstract

The following method of beam current measurement used for cathode ray tubes (CRTs) has several advantages over the moving coil ammeter method currently in use. Measurements are not affected by static charge, test gear is not directly connected to high voltage circuits, measurement of peak current is possible, and the apparatus should not require frequent re-calibration. Measurements of the very low beam currents such as are found in the cathode-anode circuits of CRTs, are usually accomplished by connecting a moving coil meter in series with the anode lead. The anode of a color CRT operates typically at about 25 KV and, therefore, great care must be exercised in such measurements.