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NOTE 2: Do not keep the "READ METER" button depressed longer than necessary to
take a reading in either the "GXl" or "GX5" positions. Most transistors in
crease in reading if the button is held down, due to heating of the collector
junction. The initial reading is the correct one to use.
8.
If
the transistor is a tetrode type, proceed as follows: Use the alligator clip leads;
leave terminal 3 disconnected; go through the transistor tests as described previously. After
completing the gain test ("GXl" or "GX5") connect alligator clip lead 3 (green) to terminal 3 of
the transistor, press the "READ ME TER" button and watch for a reading LOWER than the previ
0us "GXI" or "GX5" reading.
If
the reading does not differ from the "GXl" or "GX5" reading,
then the condition of the tetrode connection of the transistor should be questioned.
Crystal Diodes
•
Connect the cathode
(+)
of the crystal diode to terminal 4 (black) of Model T-65. Connect
(-) of diode to terminal 2 (yellow) of Model T-65.
NOTE:
It
is extremely important that the diode be connected properly, as described above;
otherwise, the diode and instrument can be damaged. See Figure 24 for polarity
identification of various types of crystal diodes.
FI~URE
24
DIODE FORWARD TEST
1. Set Function Selector switch to "Df" position.
2. Set "AI! and "B" switches as indicated on test data sheet for forward current test of
diode being tested.
3. Depress "READ METER" button.
If
meter reading is within specified range, proceed
to diode reverse test. Otherwise, reject the diode without further test. A diode which reads
well below the minimum forward reading can damage the instrument
if
the diode reverse test
is attempted.
DIODE
~RSE
TEST
Leave diode connections as above and proceed as follows:
1. Set Function Selector switch to "Dr" position.
2. Set "A" and
"e"
switches as indicated on test data sheet for diode reverse current test.
3. Depress "READ METER" button. Reading should be below that specified under diode
reverse current.
Page 34
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