Simpson 270-5, Instruction Manual

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charged.
e. Connect the black test lead to the negative side of the circuit being measured
and the red test lead to the positive side of the circuit.
f. Turn on power in circuit being measured.
g. Read the voltage using the 0-10 figures on the black scale marked DC.
Multiply the reading by 100.
Turn off power to the circuit and wait until the meter indicates zero before discon-
necting the test leads.
4.9 AC Voltage Measurement 0-2.5 Through 0-500V
Range
Branch and distribution circuits (120/240/480V etc.) can deliver dangerous ex-
plosive power momentarily into a short circuit before the fuse/breaker opens the
circuit. Make sure that the Instrument switches are set correctly, jacks are prop-
erly connected, and that the circuit power is turned off before making connections
to such circuits.
The 270 responds to the average value
of an AC waveform. The Dial is cali-
brated in terms of the RMS value of a
pure sine wave. If the waveform is non-
sinusoidal, and depending upon its
waveform, the reading may be either
higher or lower than the true RMS value
of the measured voltage. Thus an error
may be introduced if the 270 is used to
measure a non-sinusoidal waveform.
Also, accuracy is lessened at higher in-
put frequencies (Figure 4-2).
Before proceeding with the following
steps, review the Safety Precautions in
Paragraph 4.1.
a. Set the function switch at AC (Fig-
ure 4-3).
b. Set the range switch at one of the
five voltage range positions marked
2.5V, 10V, 50V, 250V or 500V.
When in doubt as to actual voltage present, always use the highest voltage
range as a protection to the Instrument. If the voltage is within a lower range,
the switch may be set for the lower range to obtain a more accurate reading.
c. Plug the black test lead into the - COMMON jack and the red test lead into the
+ jack.
d. Turn off power to the circuit to be measured and discharge any capacitors.
!
!
2.5V.
1V
-D.C.
+D.C.
10V.
50V
μ AMPS
250V.
500V
1000V
COMMON
+1V. +50 μ AMPS.
250MV.
1000V
AC. D.C
ALL TERMINALS 1KV. MAX.
WARNING
READ MANUAL BEFORE USE
270
Figure 4-2. Frequency Response,
AC Voltage Ranges