Corrosion. 12.5VDC dont mean sh!t

[duaneage]

Meters used to be rated. A typical rating was 20000 ohms per volt. This meant that the meter offered 20K per every volt read. FET meters came along ( and VTVM before them) with high impedances of around 1M ohms per volt, effectively isolating the whetstone bridge from the circuit under test.

Today even a cheapo meter will have a high enough impedance to not affect a circuit that much.

There are more important things going on than this.

[teddux]

Meters used to be rated. A typical rating was 20000 ohms per volt. This meant that the meter offered 20K per every volt read. FET meters came along ( and VTVM before them) with high impedances of around 1M ohms per volt, effectively isolating the whetstone bridge from the circuit under test.

Today even a cheapo meter will have a high enough impedance to not affect a circuit that much.

There are more important things going on than this.

Isn't that wot i said earlier?
Oh, well...deleted.

[posplayr]

Yes, I agree with you 1,000,000%
I also state that an analog is satisfactory for the job.
The point is that the amount of current required to DEFLECT the analog needle is proportionally equivalent to the current required to "light" a bulb.

To move the needle further "full-scale" will require MORE current.

OK, I think that several people here including yourself understand the effects of meter input impedance on the measurement. We also understand the difference input impedance between an analog movement 30-40K/volt meter and a FET based (1-10Mohms) input meter.

(for those that dont know, there is a voltage divider setup between the meter and the source impedance which determines whether the meter will be reliable of not for an unloaded test.)

Here is the problem, you are calling a battery tester an "analog meter" as if it is an analog volt meter. That is only partially correct ;it is an analog movement yes, but has a very low input impedance commensurate with the source like that of a battery (only 10's or ohms per volt). Therefore it is very misleading in the current context.

An analog volt meter would have behaved very similarly to a FET meter (essentially +12V at the measurement), while your battery tester would have immediately picked up on the resistance in the bad connector.(at it is doing).

Bottom line, a Battery tester is not an analog volt meter even though the internal schematic (less the resistance values) looks the same.

On the other hand you point out a very nice feature of the battery tester; it will not be fooled like the Volt meters will.

[teddux]

OK, I think that several people here including yourself understand the effects of meter input impedance on the measurement. We also understand the difference input impedance between an analog movement 30-40K/volt meter and a FET based (1-10Mohms) input meter.

Here is the problem, you are calling a battery tester an "analog meter" as it it is an analog volt meter. That is only partially correct ;it is an analog movement yes, but has a very low input impedance commensurate with the source like that of a battery (only 10's or ohms per volt). Therefore it is very misleading in the current context.

An analog volt meter would have behaved very similarly to a FET meter (essentially +12V at the measurement), while your battery tester would have immediately picked up on the resistance in the bad connector.(at it is doing).

Bottom line, a Battery tester is not an analog volt meter even though the internal schematic (less the resistance values) looks the same.

On the other hand you point out a very nice feature of the battery tester; it will not be fooled like the Volt meters will.

I don't understand a word you're trying to say.

[Guest]

Another buzz kill

[posplayr]

I don't understand a word you're trying to say.

Sorry, I cant say it any plainer

[posplayr]

Another buzz kill

how was the food?

I was hungry all day Mon after streaching my stomach out Sun nite