CAUTION
The 20A range is unprotected and has a very low internal
resistance. Do not attempt to take a current measurement if the
current is unknown or above 20Adc.
WARNING
The instrument must be connected in series with the circuit to be
measured. Do not impress voltages across the “COM” and “V-
Ω
-
mA” terminals when set to the mADC ranges. Doing so may
result in electric shock, instrument damage and/or damage to
equipment under test.
5. Remove power from the circuit to be tested and
discharge all capacitors and inductors.
6. Connect the test leads into the circuit so that the
meter is in series with the circuit where current is to
be measured. The current should enter through the
red lead and leave through the black lead in order
for the meter to indicate in an “up-scale” direction.
7. Turn on power to the circuit under test. Read the
current on the black DC scale and use the full scale
numbers which correspond to the range selected
(in the case for the 20A range 0-20).
WARNING
Before changing ranges always de-energize the circuit
completely. An open circuit exists between the test leads during
range change.
8. If the reading is less than 1/2 amp, repeat steps 5
and 6 with the switch set on the 500mA range and
the test leads in the V-
Ω
-A terminal. Repeat the
above procedures until the reading is in the upper
half of the scaleplate.
9. Turn off the power to the circuit under test.
Discharge all capacitors and inductors. Remove
8
Sec. 4 PREPARATION FOR USE
This procedure should be followed before each and every
use.
CAUTION
Before attempting to use this meter be certain to read this
operating instruction thoroughly and completely. Failure to follow
these instructions may result in electrical shock, instrument
damage and/or damage to equipment under test.
1. Inspect the SP-152A Analog Multimeter for any
signs of damage to the thermoplastic case. Do not use
if cracked, distorted, excessively dirty or any other
abnormal condition exists. Refer to sec. 7.
2.Rotate the selector switch one full turn. Check that
the switch clicks into each of the 20 positions and has
no excessive play in each position. Do not use if the
switch is loose. Refer to sec. 7.
3. Inspect the TL-56 test leads for any signs of damage.
Check for cracks in the insulation, broken or damaged
probes, loose probe pins or bent probe pins. Do not
use if any abnormal conditions exist. Refer to sec. 7.
4. Place the SP-152A Analog Multimeter on a flat
horizontal surface. Using a small screw driver adjust
the “zero adjust” screw until the meter movement
pointer lines up with the “0” reading on the left side of
the scale plate.
5. Insert the black test lead into the “-” (Com) terminal
of
the SP-152A and the red test lead into the “+”
(V-
Ω
-A) terminal. Make certain that the leads are
seated all the way into the SP-152A and fit snugly. If
the fit feels loose do not use the SP-152A or the test
leads. Refer to sec. 7.
5
