April 10, 2017

Digital Multimeters

At least 20 years ago I purchased a used Fluke model 77 multimeter and have used it seemingly every day since I purchased it. It seemed expensive at the time, but was one of the single best purchases I have made in my life.

A meter is a tool, and one of my rules with tools is to buy the best quality tools that are available. There are rare exceptions, but they are just that, exceptions.

During some idle time, I got to wondering what the options were for a person buying a meter in this day and age. There is the top of the line Fluke 87 for $350, and there are things like the well reviewed Innova 3320 for $20. Is it worth paying over 15 times as much for the Fluke 87 and why? What is available in between?

Different people have different expectations from a meter. I should make my world view clear. I want a big meter (like my brick sized 7 inch long Fluke). I want it to be rugged enough to stand some abuse, in particular I like the rubber armor on my Fluke. I am not interested in a small calculator sized meter that I can put in my pocket. These may have their place in the glove compartment of your car. All I really want from my meter is high quality volts and ohms. A beeping continuity test is almost essential, but I rigorously avoid measuring amps because that is well known as the number one cause of blown out meters. I view cheap meters that measure temperature, capacitance and humidity with skepticism. I feel these are gimmicks to sell trashy meters.

A quick look on Ebay shows plenty of Fluke model 77 meters for prices in the $50 to $100 range. I would grab one of those before a new inexpensive no-name meter.

Safety and CAT ratings

CAT 1 - safe for use in equipment with transformer derived power.
CAT 2 - safe for use on AC power outlets.
CAT 3 - safe for use in braker panel.
CAT 4 - safe for use in meter boxes and outdoor power lines.
It is unclear what the CAT rating of my old Fluke 77 is. Mine is not even a series II (there are also III and IV). It should probably considered CAT 1, but I use it for CAT 2 all the time. The low current range is unfused. The newer Fluke 77-III is CAT 3 to 600 volts.

Cheap meters

A friend has a Samyo VC9808 that has served him well. Now you can buy a Samyo VC9808+ and maybe the plus gets you something more. This unit costs $35 and is not autoranging. It does offer inductance and capacitance measuring, albeit via an awkward socket on the face of the meter.

I purchased a Holdpeak 4070L for $11.00. It measures only resistance, capacitance, and inductance -- no voltage or current measurement! It seems satisfactory so far, and is available on Amazon, as is the Samyo.


The best resources seem to be online videos.
Have any comments? Questions? Drop me a line!

Tom's Electronics pages / tom@mmto.org