Simpson 270-5, Инструкция по эксплуатации

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circuit power. When making measurements on the 50 μ A/250mV, 1 volt, or 10 amp
range, polarity can be corrected only by interchanging the test lead connector to
the current.
4.3 Measurement Of Unknown Voltage Or Current
If the approximate voltage or current to be measured is known then the correct
range may easily be selected. However, particularly when working on faulty
equipment, the voltage or current is sometimes unknown or much higher than
normal and anticipated. When working on unfamiliar or unknown equipment,
always begin a measurement using the highest range available on the Instru-
ment. Once it is determined that the voltage is within the limits of a lower range,
change to the lower range.
4.4 Test Leads
Test leads are provided with accessory screw-on alligator clips which may be
attached to the probe tips. Eliminating the need to hand-hold test prods to a
circuit for extended periods, the test clips also reduce hand proximity to a high
voltage circuit while energized. Circuit power must, of course, be turned off and
any charged capacitors discharged before connecting or disconnecting clips to
or from the circuit.
4.5 DC Voltage Measurement 0-250 mV Range
NOTE: For polarity reversing see paragraph 4.2.
Before measuring voltage review the SAFETY PRECAUTIONS listed in para-
graph 4.1. Also, when using the 270 as a millivoltmeter, care must be taken to
prevent damage to the indicating instrument from excessive voltage. Before
using the 250 millivolt range, use the 1.0-volt DC range to determine that the
voltage measured is not greater than 250 millivolts (or .25 volt DC).
a.
Set the function switch at +DC (Figure 4-1).
b. Plug the black test lead in the - COMMON jack and the red test lead into the
+50
μ A/250mV jack.
c. Set the range switch at 50 μ A COMMON position with 50V.
d. 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.
e. Read the voltage on the black scale marked DC and use the figures marked
0-250. Read directly in millivolts.
4.6 DC Voltage Measurement 0-1V Range
a. Set the function switch at + DC (Figure 4-1).
b. Plug the black test lead into the - COMMON jack and the red test lead into the
+ 1V jack.
c. Set the range switch at 1V (COMMON position with 2.5V).
d. 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.
e. Read the voltage on the black scale marked DC and use the figures marked