In the SND mode, the SonalertTM also
When testing analog devices or circuits, use
indicates good devices by beeping out of
the low range. Analog circuits contain many more
phase with the amber light. The intent of the
single junctions. Defects in these junctions show
SND mode is to permit the operator to perform
more easily when using the low range. Also, the
in-circuit tests on transistors or diodes
54-ohm internal impedance in the low range
without having to look at the light display.
makes it less likely that parts in parallel with the
device under test will sufficiently load the tester
The third mode is the METER mode. You can
to alter the signature.
only use this for out-of-circuit testing. In the
When testing an op amp in-circuit, compare
METER mode, you may measure Beta
it directly to a known good circuit. This is because
the many different feedback paths associated with
and material identity. Also, you can measure
emitter base voltage, base current (Ib), and
op amps can cause an almost infinite number of
collector current (Ic). There are four ranges for
signatures.
the Beta mode--one for small signal transistors,
Often when checking a Zener diode in-circuit,
two ranges for medium power transistors, and one
it will not be possible to examine the Zener region
due to circuit leakage. If you must see the Zener
for large power transistors.
In the VIS mode and the SND mode, the
region under this condition, unsolder one side of
maximum voltage, current and signal levels
the diode to eliminate the loading effects of the
applied to the device under test are within safe
circuit.
limits. Therefore, the device under test will receive
HUNTRON TRACKER 1000. --Bipolar
no damage nor will any adjacent circuitry.
This instrument will test transistors and diodes
integrated circuits containing internal shorts
in-circuit in the VIS or SND mode if the total
produce a resistive signature (a straight line). This
dynamic shunt impedances across the junctions
line begins in the 10 o'clock to 11 o'clock position.
are not less than 270 ohms. Also, the total
It ends in the 4 o'clock to 5 o'clock position on
the display when using the low range. This type
dynamic shunt for the emitter to collector must
of signature is always characteristic of a shorted
not be less than 25 ohms. If such should occur,
the test set will give the indication for a SHORT.
integrated circuit. It results from a resistive value
The 8-inch meter, which reads from left to
of 4 to 10 ohms, typical of a shorted integrated
right, has two scales marked 0-10 and 0-50. The
circuit. A shorted diode, capacitor, or transistor
O-10 range is used in the leakage collector current
junction always produces a vertical (12 o'clock)
and Vbe (IDENT) modes. The 0-50 range is used
straight line using the low range.
in the BETA modes. Notice a mark on the meter
just short of half-scale with the nomenclature
HUNTRON TRACKER 2000. --Bipolar
GERMANIUM and SILICON. This mark is the
integrated circuits containing internal shorts
reference in the IDENT mode. As the meter
produce a resistive signature (a straight line)
markings show, those readings below the mark
beginning in the 1 o'clock to 2 o'clock position.
This signature ends in the 7 o'clock to 8 o'clock
show the device material is germanium. The
readings above the mark show the device is silicon.
position when using the low range. This type of
On the slanting horizontal panel immediately in
signature is characteristic of a shorted integrated
circuit. This results from a resistive value of 4 to
front of the meter face are the appropriate test
10 ohms. A shorted diode, capacitor, transistor
sockets and two push-button switches. One switch
is ZERO and the other BETA. On the vertical
junction, etc., always produces a vertical (12
front panel immediately below the push-button
o'clock) straight line when using the low range.
switches are knobs marked ADJ and CAL. At the
Automatic Transistor Analyzer Model 900
top center is the POLARITY switch marked PNP
and NPN. In the center of the vertical front panel
You can use this instrument to test bipolar
is the RANGE switch, the FUNCTION switch
and the SonalertTM. Near the bottom of the
transistors and diodes in any one of three different
vertical front panel are the probe jacks. The slide
modes. Two modes, the VIS and SND, can be
switch for turning the instrument on and off is
used either in-circuit or out-of-circuit.
also in this location.
In the VIS mode, red and green lights
VIS MODE: TRANSISTOR. --To test
flashing in or out of phase with the amber
transistors with the visual indication only, turn
light show the condition of the device under test.
