Section 11.2 Digital Multimeter (DMM)
The handheld digital multimeter (or DMM) is commonly used to measure
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voltage (DC and AC),
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current (DC and AC),
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resistance,
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continuity, and
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other lesser-used quantities such as frequency.
In voltage and current modes, the internal design of the DMM is such that it has negligible effect on the circuit being measured. That said, you should always spare a moment to consider whether the input impedance in each mode is of the appropriate size to minimize the effect on the measured circuit.
The use of the DMM varies based on what quantity is being measured. Note that the meter must be connected:
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in parallel to measure voltage or resistance, and
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in series to measure current.
