Metrology is for you.

https://www.eevblog.com/forum/metrology/

Dat be true. Measurement Technology = Metrologist.

Ron

 

For a lot of measurements the requirement is to know if the measurement "is close enough", or "is not close enough"!
When I check the mains voltage to see if it is OK or not, 112 to 124 volts is "OK", if it is below or above there is probably a fault somewhere.

 

For a lot of measurements the requirement is to know if the measurement "is close enough", or "is not close enough"!
When I check the mains voltage to see if it is OK or not, 112 to 124 volts is "OK", if it is below or above there is probably a fault somewhere.

I like to calculate a measurement then do the experiment on a breadboard and see my measurements as close to my theory as possible, taking in to account component and meter tolerance of course.

 

I like to calculate a measurement then do the experiment on a breadboard and see my measurements as close to my theory as possible, taking in to account component and meter tolerance of course.

Yet you don't seem to actually be doing that. You were worried about a 30 mV difference between the readings of two meters when the range of uncertainty of either meter spans over 100 mV.

 

Yet you don't seem to actually be doing that. You were worried about a 30 mV difference between the readings of two meters when the range of uncertainty of either meter spans over 100 mV.

I worry about ANY discrepancy

 

I worry about ANY discrepancy

Then that's incompatible with the claim that you are taking into account component and meter tolerances. You really can't have it both ways.

 

Then that's incompatible with the claim that you are taking into account component and meter tolerances. You really can't have it both ways.

Either i am not good at explaining things or you are not good at understanding things but in any case i'm not here to argue with people.

i'll leave it here.

 

I worry about ANY discrepancy

Living in the real world means having to live with compromises. There is no such thing as being perfect.

 

Living in the real world means having to live with compromises. There is no such thing as being perfect.

Yes i am learning i need to be less pedantic in my experiments

 

Living in the real world means having to live with compromises. There is no such thing as being perfect.

Engineering in THE REAL WORLD always involves some amount of compromise, either in cost versus perfection , in performance vesus cost, or in safety versus performance. OR in some similar combination that I did not mention..Strive for perfect but live with what you can reasonably get.

 

Be it any test equipment, we choose a piece of TMDE (Test Measurement Diagnostic Equipment) based on the uncertainty we can live with. For the hobby enthusiast it often comes down to cost. There are always tolerances as has been covered, nothing is perfect so we choose what we can live with for a given task. We also have cost to consider and the more accuracy the more the cost. Can't make a silk purse from a sow's ear. Amazing what we have today verse 20 or 30 years ago.

Ron

 

Be it any test equipment, we choose a piece of TMDE (Test Measurement Diagnostic Equipment) based on the uncertainty we can live with. For the hobby enthusiast it often comes down to cost.

Ron

Yes Ron, i built a wien bridge oscillator which gave a beautiful output but i needed something to give me a readout of frequency and amplitude etc, so i sold a guitar yesterday and spent some cash on a proper function generator which is a beauty although still classed as budget, but still better than trying to use a breadboarded oscillator...i guess hobby electronics is as expensive as we wish to make it.

 

Yes Ron, i built a wien bridge oscillator which gave a beautiful output but i needed something to give me a readout of frequency and amplitude etc, so i sold a guitar yesterday and spent some cash on a proper function generator which is a beauty although still classed as budget, but still better than trying to use a breadboarded oscillator...i guess hobby electronics is as expensive as we wish to make it.

Sounds like my brother who collects guitars.

Ron

 

Many years ago I got a great deal on a modular Frequency counter. That was back when HP was cutting product prices by making seperate function modules that would all work with one display module. Still quite expensive stuff, but good quality. I had used that model at work and I new that they could be tricky. So I bought it at a great price, "As Is, not working." I got it home and discovered that the problem was that it was never seeing the signal to count. So I opened it up and discovered that the resistor in series with the input was burned out. So I put in a new 47 ohm, 1/8 watt resistor. THAT was the only damage!
My point being that used equipment CAN be a great deal.

 

@tsmspace You mentioned battery resistance. You cannot measure battery resistance with a multimeter. If you are doing this, it is no wonder that you are killing your multimeters.

Some new , low-cost multimeters are automatic. They are not pricy and work fine.

 

One of the biggest mistakes is your fingers when measuring ohms you cant hold the leads to the resistor with your fingers

 

Either i am not good at explaining things or you are not good at understanding things but in any case i'm not here to argue with people.

i'll leave it here.

I may be mistaken but that view is antithetical to learning. Is that the case? Argument is the rhetorical skill of persuasion, a necessary component of knowledge transfer. It took two whole years to write and ratify the Constitution, arguably the greatest intellectual achievement of the 18th century.

 

Yes Ron, i built a wien bridge oscillator which gave a beautiful output but i needed something to give me a readout of frequency and amplitude etc, so i sold a guitar yesterday and spent some cash on a proper function generator which is a beauty although still classed as budget, but still better than trying to use a breadboarded oscillator...i guess hobby electronics is as expensive as we wish to make it.

It is entirely possible to build an accurate frequency counter that has a range adequate enough to be useful, and a stable enough time base to be accurate. Unfortunately, there are also plans published for a frequency counter using a 555 timer IC as the time base. That version is a toy.

 

It is entirely possible to build an accurate frequency counter that has a range adequate enough to be useful, and a stable enough time base to be accurate. Unfortunately, there are also plans published for a frequency counter using a 555 timer IC as the time base. That version is a toy.

Yes the one i built is very accurate to 1 kHz and stable, the problem is it is fixed at 1 kHz and i needed a variable output to explore filters so i bought a ready built one last week, not only that but the one i bought looks better and has more features like sweep which i will maybe use down the road, i guess if i had boxed my old one instead of leaving it on breadboard i would have been proud of it but i decided to spend some cash and as i said have the extra functions.

 

For evaluating filters both amplitude and frequency need to be known, and also controllable. You would find that having a frequency counter separate from a function generator is more flexible.