Heathkit IT -3120 User Manual

Page 22
The following chart shows the three classes of transistors,
possible applications, and the
approximate operating current
for each class. Use the figures in the current capability
column when you select the
current range for a test.
CLASS
APPLICA T ION
CURRENT
CAPABILITY
SIGNAL
AUDIO, 1 mA - 10 mA
RF, IF
I
I
INTERMEDIATE
AUDIO,
10 m A - 100 m A I
POWER
SWITCHING
POWER
AUDIO,
100 mA - 1 A
REGULATOR,
OUTPUT
- - - - - ----
I
I
,
I
The beta scale of the meter has three calibration points CAL
Xl0, CAL X5, and CAL Xl . The CAL Xl0 setting is used
most often when transistors are tested out of the circuit.
The chart in Figure 4 shows the relationships of the various
current ranges and the calibration settings. The 100 mA
current range, for instance, supplies a maximum of 100 mA
collector current when the CAL Xl0 setting is used . In this
case and as a general rule, the beta of a transistor is the
meter
indication mu I tipl ied by the cal ibration setting.
CURRENT
RANGE
CALIBRATION
SETTING
COLLECTOR
CURRENT
BETA
MULTIPLICATION
FACTOR
BETA MULTIPLICATION
FACTOR AFTER SWITCHING
TO
NEXT LOWER CURRENT
RANGE
100
~lA
Not Used
1
mA CAL Xl
CAL X5
CAL XlO
.1 mA
.5 mA
. 1 mA
Xl
X5
Xl0
NOT AVAI LABLE
NOT AVAILABLE
NOT AVAILABLE
10 mA CAL Xl
CAL X5
CAL Xl0
1 mA
5mA
10 mA
Xl
X5
X10
Xl0
X50
I
X100
100 mA CAL Xl
CAL X5
CAL Xl0
10 mA
50 mA
100 mA
Xl
X5
X10
X10
X50
Xl00
J
1 A
CAL Xl
CAL X5
CAL X10
.1 A
.5 A
1 A
Xl
X5
Xl0
X10
I
X50
Xl00
-
- - ~
I
-
I
~UOJ§i*BM
For example:
I
Meter indication = 3.5
Calibration Setting =
CAL Xl0
BETA = 3.5x 10 = 35
I
However, if the meter indication is greater than 50, press the
I
next lower current range switch (in this case, 10 mAl and
multiply the new meter indication by 100. Notice that this
new
current range provides an additional multiplication
factor of 10.
EXAMPLE:
Meter indication = greater than 50
Select
next lower current range (additional factor of I
10)
New meter
indication = 6.5
Calibration setting =
CAL X10
BETA=6 . 5x lOx 10=650
I
I
Keep in mind that the next lower current range can be used
only when the meter indication is greater than 50 and only
for the 1 A, 100 mA, and 10 mA current ranges.
I
I
I
I
I
I
I
I
Figure 4
I
I

Heathkit IT -3120 Specifications

General

Brand	Heathkit
Model	IT -3120
Category	Test Equipment
Language	English