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Multimeter
Beginner
Combined instrument for V, I and R.
One instrument to measure V (AC/DC), I and R using switches that choose the shunt or series resistance; digital versions use ADCs.
Check the range and the lead position (A vs V) before connecting.
Measure resistance only with power off.
In more detail
A multimeter combines the functions of an ammeter, voltmeter and ohmmeter in one instrument. It is selected by a switch for measuring current, voltage or resistance.
Real-world uses
- Electricians use multimeters for fault finding.
- Hobbyists use multimeters to test components.
- Technicians use a multimeter to check voltages, currents and resistances when repairing electronic equipment.
Open the interactive lesson, with simulation and quiz →
Frequently asked questions
Can I measure current by connecting across a supply?
No. Measuring current requires connecting in series, and wrong connections can damage the meter.
Why does my meter read zero?
It may be set to the wrong range, or the circuit may be open.
How do I measure current safely?
Connect the ammeter in series, with the correct range selected, so the meter does not overload or short the circuit.
Related topics in Current Electricity & Circuits
Potentiometer · Ammeter and voltmeter · Galvanometer · Maximum power transfer · Thevenin's theorem · Norton's theorem