EEVblog Electronics Community Forum
Electronics => Repair => Topic started by: TheAmmoniacal on March 04, 2018, 06:58:07 pm
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I bought a small high-voltage power supply some time ago (320 V DC, 500 mA, 80W) for use in electrophoresis (biology stuff), as I bought it used on eBay I did some simple health checks and cleaning. In measuring the output on the scope I noticed quite a bit of noise and ripple, is it faulty?
According to the specifications the ripple is max 20 mVrms and 1 mArms. I don't have a good unit to compare it against, and not sure how much ripple and noise I should expect from a small HV switching supply like this, anyone else know if this is normal?
This how I measured it:
(https://i.imgur.com/3GA16VC.jpg)
This is what it looks like in CV mode (19 V), 499 mA. Audible whining noise.
(https://i.imgur.com/xahiRUL.jpg)
This is CC mode (20 V), 500 mA (same scale as the one above)
(https://i.imgur.com/BP9LdGf.jpg)