Multimeter Dial Symbols — A Field Guide from an EE Who's Fried Enough Meters to

[Chingy]

https://www.chinyoo.com/multimeter-symbols-guide/

Every few weeks someone posts a blown fuse or a meter that "just stopped reading" and the root cause is almost always the same: they didn't actually know what the dial position meant. So here's a working engineer's breakdown of the symbols you'll find on a typical handheld DMM, what they actually do, and where people get burned.

V, mV — DC Volts
Straight lines over the V. This is your DC voltage range. On a handheld, mV is usually a separate position or a shifted function. Input impedance is typically 10 MΩ, which is fine for most logic and supply rails but will load high-impedance nodes. If you're probing a reference divider above a few hundred kΩ, know that your meter is part of the circuit.

V~ — AC Volts
Wavy line. Most handhelds are averaging or True-RMS. If it doesn't say "True RMS," it's averaging and will lie to you on non-sinusoidal waveforms. Bandwidth is usually 40 Hz–1 kHz on cheap meters; don't try to measure switching noise with it.

A, mA, µA — Current
The tricky one. Current is measured in series, and the shunt is internal. On most handhelds, the µA/mA range uses a different jack than the 10 A range, and the 10 A range usually has a separate fuse. Cross the jacks and you'll blow the 10 A fuse or, worse, dump load current through the mA shunt. Also: never measure current across a voltage source. That's a dead short.

Ω — Resistance
Two-terminal, unpowered measurement. The meter sources a small current and reads the drop. Anything above ~1 MΩ is sensitive to finger contact and probe lead resistance. For low-ohm work, use relative mode or a 4-wire meter.

⏛ / Diode — Diode Test
Shows forward voltage drop. Typical silicon is 0.5–0.7 V, Schottky 0.2–0.4 V. If it reads OL both ways, the junction is open. If it reads ~0 V both ways, it's shorted.

))) — Continuity
Usually shares the diode position. Beeps below some threshold, often 30–50 Ω. Don't trust it for anything below a few ohms — it's a go/no-go indicator, not a precision measurement.

Hz — Frequency
Counts zero crossings. Works fine on clean digital signals, gets confused by noise and slow edges. Check the meter's trigger threshold before trusting it on a 3.3 V signal.

CAP — Capacitance
Handheld cap meters are slow and inaccurate below ~1 nF. Fine for bulk electrolytics, useless for compensation networks.

°C / °F — Temperature
Usually a K-type thermocouple input. Cold-junction compensation is in the meter, so accuracy depends on the meter's ambient temp. Don't expect better than ±2 °C.

The jacks matter more than the dial.
COM is your reference. VΩmA is the low-energy input. 10A is the high-current input with its own fuse. If you're not sure, start on the highest range and work down. And if you're measuring something you can't afford to short, put the meter on volts first and check the jacks before you even touch the circuit.

Final thought: the symbol guide on the dial is not decoration. Every position has a failure mode. Learn the failure modes and you'll stop blowing fuses.

[Slh]

When I had the opportunity to introduce an electrical safety course at work, the lowest level gave you the right to use a multimeter.

I got a cheap multimeter with cheap fuses and told the Testee (PUT? - person under test) to measure voltage across a resistor and current through it. The plan was that if they did make a mistake it was both cheap (standard mains plug fuses) and they would learn from it.

The course was put in place in response to someone who claimed to be a power electronics engineer but made exactly the same mistake three times in three weeks with current measurements and a proper (expensive fuses) multimeter...