Clamp ammeter specs

[Snowman9000]

On an inexpensive clamp ammeter, the DC current spec tolerance is 3.0% +6.
What does the +6 mean?

[MEXICOWANDERER]

Error is normally based on the range selected

3% + - 6

On a 100.0 range setting

% = 97.0 to 103.0

at one hundred amps reading, 100.0 on the dial

plus minus six digits 97.0 minus 6 = 96.4
to plus 103.6


Now, do you see why I squawk about my 5 digit voltmeters? 1.5% error = - 3 digits.

The cheapo Bang Good clamp on ammeter I have reads up to 40.00 on low scale and it is FAR more accurate than the hurricane destroyed Triplett that cost three times as much.

One amp resolution is fine for me at 500 amperes.

[Snowman9000]

So what is the error range for a reading of 1 amp? Depends on the decimal places after the 1?

[DrewE]

2oldman wrote:
Then shouldn't it be ±6?

The +/- applies to both the 3% (of the reading) and the 6 counts. In other words, it's +/- (3% plus 6 counts); for readings that are well lower than full scale, the 6 counts could easily be a much greater error than the 3%.

[ktmrfs]

2oldman wrote:
Then shouldn't it be ±6?

no.

OK, a good digital meter will have spec reading something like

+/- X% of reading +/- Z counts

E.G. +/- 2% +/- 6 counts

usually AC accuracy is worse than DC accuracy,

For AC accuracy a frequency range and crest factor range is usually specified. Crest Factor= Peak to RMS ratio. Crest factor for a pure sine wave is 1.414. The peak voltage is 1.414 times the RMS value. Square wave centered on 0V has a crest factor is 1.

[wa8yxm]

To me it means it may round UP on 4

IEL 20,4 anps might show as 21 amps.

[MEXICOWANDERER]

Gotta remember these ads are formulated by folks who understand



I have a cheap digital meter I purchased from BANG GOOD and it works great. The 40 amp DC scale measures amperage like 16.36 so the least significant digit is truthfully not significant

[2oldman]

Then shouldn't it be ±6?

[westend]

Range of tolerance with the last significant number having a tolerance spread up to 6.