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.

Relevant Pages

  • Re: Checking a BC548B NPN Transistor?
    ... Starting with the pot cranked to maximum resistance, ... The meter will now be indicating the base current and all ... "While a normal meter can test go or no go it cant test HFE ... built-in beta tester, beta can be tested at only one point on the ...
  • Re: Fluke 77 ohms reading cal off
    ... As you have found it is the only adjustment. ... an accurate 300mv or 3Volts and adjust the pot. ... Voltage readings was about .1 volt difference between the two on DC volts. ... For a digital meter, that 0.1V difference could be significant (unless you're ...
  • Re: Tube Testers
    ... I wouldn't own a tube tester unless it measured ... But I looked at the manual, and the instructions ... That meter has a mark for "Line Adjust" at dead center. ...
  • Re: black star multimeter 3225
    ... then you complain about the price of petrol. ... if you still have interest in calibrating that meter. ... Mercury cells were good enough to use as a secondary standard when calibrated, and if not, new ones wer good to 5 digits. ...
  • Re: truck electric leak
    ... so you need a way to calibrate or at least zero it. ... The simple way to use it would be to connect a 1 - 5K pot across the ... Use the pot to zero the meter when current = 0. ... shorting switch to zero the meter reading without disconnecting the ...