The 3-1/2 digit models I have tried read frequently a fifteenth to two tenths of a volt in error. For five dollars I do not need error. The 5 digit models are frequently within 3 thousandths of a volts with one another. It's all not about thousandths of a volt -- it's about accuracy, stability and money. Heck, tape off the least significant digit if you want. The 5 dollar meters agree with my bench meter that cost 3 thousand dollars in 1995 and was last certified in August 2017 when I had a pacemaker implanted. The bench meter is a 6-3/4 digit unit. It stays wrapped in plastic with a ton of Sodium Polyacrylate powder.
After having purchased perhaps a dozen panel meters and having remained stable over a 7-year period (The BORG) I feel confident enough to recommend them. The 3-3/4" digit Fluke agrees with the Bench meter and the 5 digit panel meter. But a 5 digit rather pricey Triplett meter is in error by 5 hundredths of a volt. And has drifted 4 points. Like it or not I have discovered that power supplies that hunt are not stable and are soon zombies.
