Re: black star multimeter 3225

g.knott wrote:

Jamie wrote:

g.knott wrote:

Does anyone know how to calibrate this? Made in the UK.

First you sit down and eat your tea and crumpets.
then you complain about the price of petrol.
then you complain about the Americans. ( that is if you
are a Brit to start with). and after all of that.
if you still have interest in calibrating that meter.
You could then start looking at the manual.
personally, I don't thing the meter should nerd
calibrating. If so, and you're looking for very high
accuracy? I don't think you should be doing it.

Over here in good old USA. a Simpson 260 Analog
meter is considered a standard. Or at least, it once
was. ( I have one btw, in very good condition)

Ah another helpful American ;-)

The point is that I have a class of students that must calibrate a piece of electronic equipment according to the manufacturer's instructions.
We have lots of these meters and since they are battery driven they are safe to dismantle.
I was hoping someone has done this.
Well, if you really want to "calibrate a piece of electronic equipment according to the manufacturer's instructions" thenyou need to get those instructions.
And since you are referring to a mass production unit, any calibrating (pot tweaking) done at the factory is done according to *internal* methods and thus is !proprietaty! and will not be disclosed.
So, the best you can do in this case is "calibrate a piece of electronic equipment according to best (to be determined) efforts".
Take one apart and tweak only one pot at a time, say by only one screwdriver blade-width, and check all scales to find what changed.
This way, each adjustment can be labelled "capacitance zero", "resistance", "voltage", "unknown".
*RESET* the tweak when done.
Use a digital camera for a closeup and label the photo (use arrows to pots) accordingly; print copies along with a suggested procedure that you determine.
You can use 0.1% resistors and 2% capacitors as "standards", along with an off-the shelf precision voltage regulator.
Current measurements are never adjustable; they depend on the internal shunt accuracy and voltage measurement accuracy.