B) Voltage Measuring "V; C) Low-Pass Filter (Hfr = High Frequency Reject) - VOLTCRAFT VC950 Operating Instructions Manual

b) Voltage measuring "V"

Proceed as follows to measure direct voltages "DC" (V
and alternating voltages "AC" V
Switch on the DMM and select measuring range "V". For low
voltages up to 100 mV, select "mV". Observe that the maximum
values (also see chapter Technical Data) must not be exceeded
while measuring.
- P lug the red measuring line into the V measuring jack (7) and
the black measuring line into the COM measuring jack (8).
- C onnect the two measuring prods to the object to be meas-
ured (battery, circuit, etc.). The red measuring prod indicates
the positive pole, the black measuring prod the negative pole.
- The polarity of the respective measured value is indicated on
the display together with the current measured value.
If a minus "-" appears in front of the measured value for
direct voltage, the measured voltage is negative (or the
measuring lines are swapped). The voltage range "V DC/
AC" has an input impedance of >10 MOhm.
- A lways remove the measuring lines from the object to be measured after completion of the measurement and
switch off the DMM.

c) Low-Pass Filter (HFR = High Frequency Reject)

Never use the low-pass filter option to test for presence of dangerous voltages! The present volt-
ages may be higher than indicated.
Always perform voltage measurement without the filter first to recolonise any possible dangerous
voltages.
This function can only be activated in the alternate voltage measuring range.
The DMM is equipped with an alternating current low-pass filter. This is an alternating voltage measurement routed
through a low-pass filter that blocks undesired voltages exceeding 800 Hz.
- Switch on the DMM and select measuring range "V". For low voltages up to 100 mV, select "mV".
- P lug the red measuring line into the V measuring jack (7) and the black measuring line into the COM measuring
jack (8).
- Press the "HFR" button. The display shows "HFR".
- C onnect the two measuring prods to the object to be measured (battery, circuit, etc.). The red measuring prod
indicates the positive pole, the black measuring prod the negative pole.
- The polarity of the respective measured value is indicated on the display together with the current measured value.
- Press the "HFR" button again to deactivate the low-pass filter.
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