TM 9-6625-1754-14
SECTION V. APPLICATION
both directions, the silicon diode is probably
tion
shorted.
d. Set the function/range switch to the X10K
Maintenance calibration of dc voltage power
OHMS position.
supplies is performed using the multimeter as
follows :
good silicon diode should conduct in the forward
Note. This procedure is equally applicable to sources
direction only. If no conduction is evident in
of ac voltage.
either direction, the silicon diode is probably
a. Set the mode selector switch to DIGITAL
open.
MODE.
b. Set the function/range switch to the appro-
Measurements
priate VOLTS DC position.
c. Set the digit wheels to indicate the desired
The dc voltage and current measurement
voltage level,
capability of the multimeter may be extended
d. Connect the multimeter to the power supply.
at reduced accuracy as follows:
e. Adjust the power supply voltage control
a. Set the mode selector switch to DIGITAL
for the mid-scale target indication on the mul-
MODE.
timeter.
b. Set the digit wheels to 100.
c. Select the desired function/range switch
position. See table 8 for function/range switch
conductor Circuits
settings.
measurements or circuit tracing without fear of
Capability
damage to expensive semiconductor elements.
Meter mid-scale Meter full-scale
Function/Range
indicator
Division scale
switch position
of 50 mv on the Xl through X1K OHMS ranges
indication
20 a dc
10 a dc
0.4 a da
0.1 mA DC
with a maximum current of 20 ~a on the X10K
1 mv dc
25 mv dc
50 mv dc
0.1 mA DC
and X100K OHMS ranges to the circuit under
100 mv dc 200 mv dc
4 mv dc
1 VOLT DC
test.
silicon devices is greater than the 50 mv applied
The sensitivity of the dc voltage measurement
by the Xl through "Xl K OHMS ranges of the
capability of the multimeter may be extended as
model 300M. This permits resistance measure-
follows :
ments in circuits containing silicon devices with
Note. In this operation the sensitivity of the multim-
no noticeable shunting error contribution.
eter, using conventional terminology, is 50,000
d. The current limiting on the X10K and
ohms per volt. The accuracy is 2 percent of
full-scale.
X100K ranges allows making resistance measure-
ments in circuits containing silicon devices with-
a. Set the mode selector switch to DIGITAL
out fear of over-dissipating any silicon junction
MODE.
present.
b. Set the digital wheels to 100.
c. Select the desired function/range switch
position. See table 9 for function/range switch
Checking of silicon diodes is accomplished as
settings.
follows :
a. Set the mode selector switch to SEARCH
Capability
MODE.
Meter
Meter-full-scale Division
Function/Range
resistance
value
switch position
b. Set the function/range switch to the X1K
indicator
10k
0.2 vdc
0.004 vdc
1 VOLTS DC
OHMS position.
100k
0.04 vdc
10 VOLTS DC 2.0 vdc
1 meg
0.40 vdc
100 VOLTS DC 20 vdc
good silicon diode should not conduct for either
10 meg
4.0 vdc
1000 VOLTS 200 vdc
polarity connection, If conduction is noted in
DC
