Simpson 260 Series - Measuring Unknown Voltages and Currents; Proper Use of Test Leads; DC Voltage Measurement: 0-250 mV Range

Operation
to these jacks (only). Because polarity reversing momentarily
interrups the circuit, it should not be done while measuring cur-
rent without first turning off the circuit power. When making
measurements оп the 504,A/250mV, 1 volt, ог 10 amp range,
polarity can be corrected only by reversing the test leads.
4.4 MEASUREMENT OF UNKNOWN
VOLTAGE OR CURRENT
4.4.1 Sometimes the approximate voltage or current to be meas-
ured is known and the correct range may easily be selected. It
is often the case, however, particularly when working upon faulty
equipment, when the voltage or current is either unknown or may
be much higher than normal and anticipated. Whenever working
upon unfamiliar or unknown equipment, always begin a measure-
ment using the highest range available on the Instrument. Once
it is determined that the voltage is within the limits of a lower
range, change to the lower range.
4.5 TEST LEADS
4.5.1 These are provided with accessory screw-on alligator clips
which may be attached to the probe tips. Aside from the con-
venience of eliminating the need to hand-hold test prods to a
circuit for extended periods, the test clips provide a means of
reducing 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.
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46 DC VOLTAGE MEASUREMENT 0-250 mV RANGE
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