D . OLTRONIX TRANSISTOR IDENTIFICATION CODE
To assure th
a
t the transistors in the Oltronix power supplies have good enough
data for their actual application, all transistors are tested with a Tektronix
Curve Tracer before they are mounted in any instrument. Certain transistors
e. g. power transistors and transistors for high voltage use pas s a more
complete test after which
a
classification mark is applied. This mark is a
letter-number combination on the power transistors and a colour dot on the
smaller transistors .
The letter indicates high
"
H
"
o r low " L" current gain.
The number shows
the maximum working voltage .
The te:::;t conditions are :
Test
Current gain
Voltage
Power transistors
T0- 3 arid T0-36
I = 2A
c
V CE= lOV
High
if
hFE
?
50
Low if hFE
<
50
Other transistors
To- 5 and similar
I = lmA
c
V CE= lOV
High
if
hFE
?
50
Low
if
hFE
<
50
Transistors with extrem ely high or extremely
low
hFE are rejected
I = 40 0mA
c
RBE
=
100 ohms
I = lmA
c
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