Hickok 539C - Model 539 C Operating Instructions; Foreword to Model 539 C Operation

OPERA TING INSTRUCTIONS
FOR
MODEL 539C
TRANSCONDUCTANCE
TUBE TESTER
FOREWORD
The Model 539C Mutual Conductance (Transconductance) Thbe Tester is designed for use
by technicians, engineers and others who demand an instrument of the very highest qua-
lity for rapid and accurate testing of vacuum tubes. Like all Hickok Tube Testers, it is
based upon the well known formula for mutual conductance,
f\ip = Gm
6
e
g ,
where ip is the plate current change, eg is the grid voltage change, and Gm is the Mutual
Conductance
(Transconductance). Mutual Conductance and Transconductance are used
interchangeably.
This instrument is equipped with three meters, all made in our own plant, and calibrated
with great accuracy.
(a) A sensitive Transconductance meter measuring micromhos in six ranges up to
60, 000 micromhos. This meter also has a scale reading to 200 volts for V. R.
tube
testing, and a scale reading to 50 megohms for leakage testing.
(b) An A. C. voltmeter which insures standardized voltages to the tube's base, and
(c) A two range (0-10, 0-50) D. C. voltmeter to accurately adjust the negative bias
on the tube's control grid. Also a scale to 100 M. A. d. c. for V. R. milliam-
peres.
Voltage adjustments are made while the tube being tested is delivering its rated
load.
NOTE: Always check a tube for shorts before pro~eeding with Mutual Conductance test.
OPERA TING INSTRUCTIONS
Read these instructions through before attempting to operate the tester.
1. There are two rectifier tubes, an 83 and a 5Y3GT necessary to operate this tester.
They are included.
The Short Lamp is a 1/25 watt, 110 volt, miniature bayonet base neon signal lamp.
This lamp will last indefinitely unless broken.
The Fuse Lamp is a standard No. 81, single contact auto bulb. This can be pro-
cured from any auto dealer or gasoline station attendant. This fuse lamp is in the
primary circuit of the transformer.
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