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Products => Test Equipment => Topic started by: MikeK on May 13, 2022, 12:21:36 am

Title: KORAD 3005P, calibration?
Post by: MikeK on May 13, 2022, 12:21:36 am
I found that mine outputs 0.51mA even with the output switched OFF.  And when set to 5mA it actually outputs 7.8mA.  Ugh.

I checked the user manual, but no info.  Can this be calibrated?  At the very least OFF should be OFF!
Title: Re: KORAD 3005P, calibration?
Post by: Electro Fan on May 13, 2022, 07:06:38 am
Here is a link to a post with an old calibration routine - there might be a newer one or one with better translation.

https://www.eevblog.com/forum/testgear/korad-display-bug/msg1218999/#msg1218999 (https://www.eevblog.com/forum/testgear/korad-display-bug/msg1218999/#msg1218999)
Title: Re: KORAD 3005P, calibration?
Post by: SHF on May 13, 2022, 11:29:54 am
I have something here in German
Title: Re: KORAD 3005P, calibration?
Post by: MikeK on May 13, 2022, 02:00:53 pm
Is having 0.51mA with the output Off even a calibration issue?  Why would there be any current at all?  An output transistor leaking current?
Title: Re: KORAD 3005P, calibration?
Post by: Forester on May 13, 2022, 03:20:44 pm
I have a KORAD 3010. When the output is off, the voltage is 6 mV,  сurrent 3.6 mA. Measured Fluke 87V. Why so - I do not know.
Title: Re: KORAD 3005P, calibration?
Post by: Electro Fan on May 13, 2022, 06:44:53 pm
On my Korad KA3005P when I set the PS to 9V, 20mA my Fluke 179 says 8.99V, 20mA with the output button on. 

With the PS still set to 9V, 20mA and the output button is off the Fluke says -112mV, -0.11mA.

With the PS set to either 9V or 5V and 5ma and the output turned on I get 5.7mA on the Fluke.

I found a newer version of the calibration routine (attached below) - probably worth giving it a try.

EDIT:  after warming up the 5.7mA reading became ~5.4mA.
Title: Re: KORAD 3005P, calibration?
Post by: MikeK on May 13, 2022, 07:11:44 pm
They appear to be saying that you shouldn't expect better than 5mV and 1mA even when switched off.
Title: Re: KORAD 3005P, calibration?
Post by: Electro Fan on May 13, 2022, 07:41:15 pm
Quote from: MikeK on May 13, 2022, 07:11:44 pm
They appear to be saying that you shouldn't expect better than 5mV and 1mA even when switched off.

I have two Korad KA3005 units (one P and one D).  Having gone through TEA, in addition to the two Korads, I've collected my share of meters (179, Brymen 789, KS 34465A, and more than several others).  After doing plenty of measuring I think the Korad at just a little over $100 more than holds it's own.  Try the calibration routine - it's a little bit hard to interpret but stick with it and I think you might be able to dial-in the Korad to an extent that will give you good confidence.  Having said that, anything can fail and it's possible your unit has some issue but I wouldn't draw that conclusion until trying to calibrate it.
Title: Re: KORAD 3005P, calibration?
Post by: MikeK on May 13, 2022, 08:14:37 pm
I tried the cal...that's the best I can get.  I'll live with it.  I might build Scullcom's millivolt meter for what I'm doing.

Thank you.