Aaaah...thanks for that input...I was messing around with several options with the voltage divider but did not allow myself the time to get it sussed...so thanks for your support good man. Cheers, Martin.
Look at the video from 30:41. The meter is clearly autoranging to the 500V range when trying to measure 50V. The clue is in the leading 0 on the display (eg. 050.02 and 050.017 in high-res mode). The meter may well be able to read slightly above its specified voltage ranges to be able to do some kind of auto-ranging hysteresis, so if you approach a range voltage limit from below it will avoid changing up a range. It is specified as a 50000 count meter, so any display above that is "bonus".
Good show! I recommend using silver plated and shielded conductors. Second, all probes should be connected to the reference source directly. Noise, hum and current loops will be greatly reduced. Best regards,
One possibility that the 50V calibration did not work might be that the meter wants a fairly stable reading...and perhaps my reference was changing by too many counts during the process... Looking forward to your BMS progress!
I forgot to mention: it is good practice to keep an anti-static grounded mat under the meter in test. Static fields build easily with plastic parts, they can also create adverse charges affecting the calibration. My two cents! Best regards,
I know this is an old video, but just wanted to shortly comment. When you were busy with the 250mV range you have used the function generator as a source, with long cables all over the place. Of course you would get 10-100uV noise anyway. As it was DC you could heavily low-pass filter the function gen, or even better you could use a simple battery and the divide... Both suggestions are low cost solutions.
You're measuring 50V with the 500V range. Your 500V range is slightly off. Your 50,000 count (I know you have an optional extra digit) meter's 50V range can only display up to 49.999V but needs 50.000V to calibrate. If you manually select the 50V range and measure the 50V the meter will either indicate "over", or 49.999V (and close below) as your reference and meter drift. Check your 50V range calibration with a voltage less than 50V. Similarly you cannot view 5.0000 V on your 5V range, etc.
Holy hell your knowledge is ridiculous!! You should change your name to The Professor or something. I’m curious to know if there is anything that you don’t know about electricity and electronics? Your teaching techniques are 2nd to none and even though I don’t understand 1/2 of what you’re talking about I still find it interesting. I’ve watched all 3 of the episodes you made for beginners with multimeters probably 3-4 times just to get it sunk in. I knew you were the right guy to watch when I saw the one video and you had at least a dozen multimeters in the background along with all sorts of technical equipment that looked very intimidating. You do such a good job at dumbing things down for us lesser intelligent people that I actually understood everything you were talking about. Since I find all your advanced videos so interesting I’ll watch them all and hopefully I’ll end up understanding some of your instructions after seeing them multiple times. Lastly I’d really like to thank you for doing such detailed almost school like lessons to help all of us that love multimeters and doing our own repairs. It helps a lot of people I’m sure.
Another way to smooth the noise is to put some capacitors after the voltage divider. Also, a 1 meg pot is probably a little high, try 100K instead. It will heat faster but it will source the meters with a bit more current and perhaps be a little less noisy but might drift much faster.
Hello, where can I download the calibration document? Your forum post doesn't seem to have it. By the way I thought I should register and the attachments would become visible (as I know some forum software doesn't let guests download attachments) but gave up after it twice kicked me out for "not being human". Apparently 314159 are NOT the first 6 digits of Pi? You may want to check your registration page - it also kicks you out COMPLETELY, forcing you to reenter all data if you make a single mistake. And quite a few actual people are going to fail your questions, never mind the obnoxious capcha (what's the point of that if you have all those questions anyway?).
The AM-160 is more accu that 289... Or not ??? I need a precision DMM for calibrate my olders DMM Flukes 7x series... Or Brymen 869S ...?? Let me know pls
I think the calibration in each range is probably not a simple offset. More likely the meter assumes the error is proportional to the input voltage, and stores a factor (which can be rolled into storing the reference voltage - probably what's shown on screen). Most errors will be of this type (input divider, reference voltage). Any fixed offset will be known from the 0V cal. Nice work on the vid, well worth breaking it to learn!
While ohms law applies to pure DC circuits, it all becomes more complex when dealing with AC and radio frequencies where reactance is involved. Noise as picked up by the meter probes is a form of RF, mixed with other electromagnetic fields, which makes it impossible to speak of high input resistance instead of impedance. It is in this context that silver plated conductors make a difference. I don't have more space to elaborate any further. Sorry.
Hi Martin, I like your videos and I guess I missed the video where you tried to trim out the 19 counts. Why would you try to trim out 1.9mV? That has to be down in the noise range especially with ordinary leads.
Yes, but you need a very good power supply capable of doing so. You need a power supply becouse the multimeter needs a current to make the measure. The system should be based on feedback: a voltage sensing at the connection between the multimeter and the power supply to keep constant 0V.
Thanks, great input...appreciate the support and feedback! Cheers, Martin.
Aaaah...thanks for that input...I was messing around with several options with the voltage divider but did not allow myself the time to get it sussed...so thanks for your support good man. Cheers, Martin.
Look at the video from 30:41. The meter is clearly autoranging to the 500V range when trying to measure 50V. The clue is in the leading 0 on the display (eg. 050.02 and 050.017 in high-res mode).
The meter may well be able to read slightly above its specified voltage ranges to be able to do some kind of auto-ranging hysteresis, so if you approach a range voltage limit from below it will avoid changing up a range.
It is specified as a 50000 count meter, so any display above that is "bonus".
Good show! I recommend using silver plated and shielded conductors. Second, all probes should be connected to the reference source directly. Noise, hum and current loops will be greatly reduced. Best regards,
Thanks...What's the best way to get 0V?
Thanks...those are the pearls of wisdom I'm looking for. Thanks for the post.
One possibility that the 50V calibration did not work might be that the meter wants a fairly stable reading...and perhaps my reference was changing by too many counts during the process...
Looking forward to your BMS progress!
I'm far from trying this, but it's kool to see the process. Thanks for sharing
Thanks Paul! Appreciate the post. Cheers, Martin.
Would be very nice if you review this DMM to check the drift after all these years.
Awesome video, I always wondered how those meters without calibration pots actually worked. Thanks
Another thing to note is that when you short the leads you are not getting 0V, because of the thermocouple effect.
I forgot to mention: it is good practice to keep an anti-static grounded mat under the meter in test. Static fields build easily with plastic parts, they can also create adverse charges affecting the calibration. My two cents!
Best regards,
I know this is an old video, but just wanted to shortly comment. When you were busy with the 250mV range you have used the function generator as a source, with long cables all over the place. Of course you would get 10-100uV noise anyway. As it was DC you could heavily low-pass filter the function gen, or even better you could use a simple battery and the divide... Both suggestions are low cost solutions.
You're measuring 50V with the 500V range. Your 500V range is slightly off.
Your 50,000 count (I know you have an optional extra digit) meter's 50V range can only display up to 49.999V but needs 50.000V to calibrate. If you manually select the 50V range and measure the 50V the meter will either indicate "over", or 49.999V (and close below) as your reference and meter drift.
Check your 50V range calibration with a voltage less than 50V.
Similarly you cannot view 5.0000 V on your 5V range, etc.
Holy hell your knowledge is ridiculous!! You should change your name to The Professor or something. I’m curious to know if there is anything that you don’t know about electricity and electronics? Your teaching techniques are 2nd to none and even though I don’t understand 1/2 of what you’re talking about I still find it interesting. I’ve watched all 3 of the episodes you made for beginners with multimeters probably 3-4 times just to get it sunk in. I knew you were the right guy to watch when I saw the one video and you had at least a dozen multimeters in the background along with all sorts of technical equipment that looked very intimidating. You do such a good job at dumbing things down for us lesser intelligent people that I actually understood everything you were talking about. Since I find all your advanced videos so interesting I’ll watch them all and hopefully I’ll end up understanding some of your instructions after seeing them multiple times. Lastly I’d really like to thank you for doing such detailed almost school like lessons to help all of us that love multimeters and doing our own repairs. It helps a lot of people I’m sure.
23:39 The figure is probably the multiplicative factor used to arrive at the 5V reading based on the input divider circuitry.
Thanks for video. Do you know how to calibrate BM789?
Another way to smooth the noise is to put some capacitors after the voltage divider. Also, a 1 meg pot is probably a little high, try 100K instead. It will heat faster but it will source the meters with a bit more current and perhaps be a little less noisy but might drift much faster.
Hello! Can I calibrate (one point at 5 volts) Brymen 867s multimeter? At least so that at low voltages the accuracy is as high as possible.
I bought an amprobe am 570 which is advertised as an industrial DMM. I'm wondering is the am 160 a supposed to be a better quality meter?
Hi!! Very good the video!
Do you know if the AMPROBE AM-140-A model can be calibrated in the same way? Thanks!!
Hello, where can I download the calibration document? Your forum post doesn't seem to have it.
By the way I thought I should register and the attachments would become visible (as I know some forum software doesn't let guests download attachments) but gave up after it twice kicked me out for "not being human". Apparently 314159 are NOT the first 6 digits of Pi? You may want to check your registration page - it also kicks you out COMPLETELY, forcing you to reenter all data if you make a single mistake. And quite a few actual people are going to fail your questions, never mind the obnoxious capcha (what's the point of that if you have all those questions anyway?).
so, apparently Sanwa PC7000 have the same way for the calibration, i think the sanwa PC7000 have the same chip with the brymen
The AM-160 is more accu that 289... Or not ??? I need a precision DMM for calibrate my olders DMM Flukes 7x series... Or Brymen 869S ...?? Let me know pls
Hello.From where I can buy that voltage reference ? Thanks , and maybe you can do a calibration video for EXTECH GX-900 .
Dear friends I need to repair hioki 3256-50 digital hitester multimeter video. Not properly working.
I think the calibration in each range is probably not a simple offset. More likely the meter assumes the error is proportional to the input voltage, and stores a factor (which can be rolled into storing the reference voltage - probably what's shown on screen). Most errors will be of this type (input divider, reference voltage).
Any fixed offset will be known from the 0V cal.
Nice work on the vid, well worth breaking it to learn!
While ohms law applies to pure DC circuits, it all becomes more complex when dealing with AC and radio frequencies where reactance is involved. Noise as picked up by the meter probes is a form of RF, mixed with other electromagnetic fields, which makes it impossible to speak of high input resistance instead of impedance. It is in this context that silver plated conductors make a difference. I don't have more space to elaborate any further. Sorry.
Hi Martin,
I like your videos and I guess I missed the video where you tried to trim out the 19 counts. Why would you try to trim out 1.9mV? That has to be down in the noise range especially with ordinary leads.
Well done Martin, Thumbs up from me.
Great video, very interesting.
Useful video 👍
Exactly. The PSU needs to be able to source and sink current rather than just source current like a normal arrangement.
Review Rish Multi 20 please
Why use a 1MOhm pot?
Johnson noise is proportional to resistence! Look at Keithley low level measurements handbook.
Yes, but you need a very good power supply capable of doing so. You need a power supply becouse the multimeter needs a current to make the measure.
The system should be based on feedback: a voltage sensing at the connection between the multimeter and the power supply to keep constant 0V.
Nice video.
I enjoy amateur metrology :)
Most likely a bipolar power supply set to 0V
it's great movie
o ooooooo oooooooo fuk this calb work.