Digital multimeters
A stated safety category, or true-RMS?
Across five multimeters, one listing states a measurement category and one offers true-RMS. They are not the same meter. This page is about which gap you can live with.
| Compared on | CAT III digital multimeter | True-RMS multimeter, 6000 counts |
|---|---|---|
| Measurement category | CAT III stated (voltage not given) | Not published |
| True RMS | Not published | Stated |
| Counts | 3½ digits | 6000 |
| Voltage range | 600 V AC/DC | Up to 600 V |
| Current range | 10 A AC/DC | AC/DC current, range not given |
| Extra functions | Resistance to 20 MΩ, continuity | Temperature, capacitance, frequency, diode, continuity |
| Probe tip caps | Not published | Supplied |
| Auto power-off | After 15 minutes | After 15 minutes |
| Listed on amazon.com | Yes | No |
A tick marks the better answer on that line only. Counting ticks does not decide the page — the two verdicts below do, because these products answer different questions.
Buy the coczow if knowing where the instrument may be used matters more than what it can measure. Stating a category at all puts it ahead of four of the five meters in the hub.
No amazon.com listing was found for this one. We hold references for other markets but none for the United States, so it may not be buyable here — which is the first thing to weigh against anything below.
Buy the Brennenstuhl if the meter will be pointed at anything modern. True-RMS is the difference between a correct reading and a systematically low one on dimmers, drives and LED supplies — and read the manual for the category it does not print.
Partly. A category and a voltage are one specification, so CAT III alone is incomplete — and it is still more than the other four meters publish. The full rating is on the instrument and in the manual.
It assumes a clean sine wave and scales its reading accordingly. On a chopped waveform — a dimmer, an inverter, a variable-speed drive — it reads low, sometimes substantially.
CAT III stated · 600 V AC/DC · 10 A · 20 MΩ · auto power-off
The only multimeter in this hub whose listing states a measurement category. It also gives its ranges plainly: 600 V AC and DC, 10 A, 20 MΩ.
Best for: Household and installation fault-finding where knowing the category matters more than the feature list.
≈ $25
True RMS · 6000 counts · 600 V · temperature, capacitance and frequency
A true-RMS meter with 6000-count resolution and a wide function list — voltage, current, resistance, temperature, diode, continuity, capacitance and frequency — with probe caps included.
Best for: Household and light installation work where waveforms are not clean and the reading has to be right.
