D) Ac Measurements; Resistance Measurement - VOLTCRAFT BB-500 DMM BLACK BOX Bedienungsanleitung

d) AC measurements

Before connecting the DMM to a power circuit to be measured in series, switch off
the mains supply to the power circuit and discharge all high-voltage capacitors first.
Do not connect the test leads to a parallel circuit when connecting the test leads to
the current input socket.
• Connect the red test lead to the mA socket and the black test lead to the COM socket (3).
• Connect the measuring tips to the current or load to be measured in series. Use the mobile
software (app) to select the mA/AC measuring function. The measured readings will be
displayed by the app. The current readings are average values.
• When all measurements have been completed, first switch off the power supply and then
disconnect the test leads from the measuring object.
e) Resistance measurement
Make sure that the circuit components, circuits and components to be measured or
any other measuring objects are voltage-free and discharged.
If the tested resistor is located within an open power circuit or the resistance
reading exceeds the maximum value of the DMM, the mobile device will show "OL"
(overload).
When measuring a resistor in series, first disconnect all voltages within the
measured circuit. Discharge all capacitors in order to ensure correct measurements.
When measuring a low resistance, the test leads will cause a deviation of
0.1 to 0.2 ohms. To get accurate readings, perform a relative measurement.
Short-circuit the measuring tips, until the displayed reading drops to a stable value.
Then touch the >REL< field on your mobile device and perform the low resistance
measurement.
If the resistance reading is not lower than 0.5 ohms while short-circuiting the test
leads, check if the test leads are loose or other connection problems occur.
Do not apply input voltages higher than 30 V/AC (mean), peak 42 V/AC or 60 V/DC,
in order to avoid hazards.
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