VOLTCRAFT VC-539 Mode D'emploi page 34

Due to the current clamp sensor's (1) permanent magnetism, the LC display (10) may show
a low reading before measurement. This is possible even if no conductor is present. To reset
the display to zero, push the ZERO button (12) before measurement.
5. Remove the current clamp from the object under test after measurement and turn off the current
clamp.
b) Frequency (Hz) / Duty cycle (%)
1. Use the mode switch (4) to select the measurement mode for frequency / duty cycle.
2. Remove the safety caps from the L-shaped test lead jacks.
3. Connect the red test lead to the red test lead jack (7).
4. Connect the black test lead to the black test lead jack (8).
5. Push the Hz% button (5) to select frequency or duty cycle measurement. In the upper right-hand
corner of the LC display (10), the corresponding symbol:
- Hz for frequency
- % for duty cycle
6. Connect the test prod to the object under test.
7. The reading is shown on the LC display (10).
8. Remove the test leads from the object under test after measurement and turn off the current
clamp.
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Measuring frequency / duty cycle