EEVblog 1636 - Ultimate Multimeter Beginners Guide

[EEVblog]

The ultimate beginners guide to multimeters. What are they, how to choose one, and how to use them to measure electrical things.

00:00 - The Ultimate Beginners Guide to Multimeters
00:35 - Display Counts Explained
01:17 - Range Switch or Push Button?
01:43 - Don't get a rechargable type or permanent backlight
02:05 - Autoranging vs Manual Ranging
03:05 - Multimeter Probes
03:36 - Rubber Holster vs Overmoulded Rubber
03:50 - Battery powered & Auto Power Off
04:06 - What can a Multimeter Measure? Voltage, Resistance and Current
04:55 - Do you need Current measurement?
05:38 - Capacitance & Continuity
06:39 - Continuity Testing Demonstrated
07:08 - Diode and LED testing
07:59 - Thermocouple Temperature Measurement
08:37 - Non-Contact Electric Field (NCV) Testing
08:57- Frequency, Duty Cycle, and Min/Max/Avg
09:18 - True RMS vs Average Responding
10:13 - Practical usage demonstrated
10:47 - Modern Multimeters are very robust
11:10 - Here is where it gets dangerous, current measurement.
12:55 - CAT Safety rating and fuses
14:23 - UL and ETL Testing Certification
14:43 - BEWARE of Battery LEAKAGE!
15:00 - Don't measure Ohms in-circuit
15:43 - Auto Touch Hold
16:17 - DC Voltage Measurements
17:35 - AC Voltage Measurement
18:08 - Current measurement demonstrated
19:50 - Capacitance measurements demonstrated
21:20 - Ohms cable measurement
22:07 - Manual ranging demonstrated
23:02 - Bargraph function
23:45 - Conclusion and Recommendations

[golden_labels]

Shared with a friend, who starts his journey into electronics.

The cable capacitance trick may also be used, if one doesn’t know the capacitance of the entire cable. Measure the broken cable from both ends. Proportion of the measured values will be roughly the proportion of cable lengths on each side of the break.

[Kleinstein]

The capacitance of cables is not that variable. A good starting point is 100 pf/m : works OK for mains cable and RG58 coax. Getting a much different value is rare.

For cheap meters of Chinese origin one should be a bit suspicious about the CAT rating. At least have a look at the fuses before using it for mains or similar high power circuits. There are a few that are somewhat OK, but also plenty of fake ratings. Just another mark claiming an independent test may as well be wrong.

[golden_labels]

Quickly looking at the actual values from a few mains cables, Kleinstein’s rule of thumb seems pretty reasonable.