You sure that is a linear reg?
Something is very, very wrong if it is, as it looks to be honking at ~60Khz and triplen harmonics of that frequency.
Thanks, yes it is only a linear regulator…..maybe the offtheshelf control chip has a microcontroller inside it which works at high frequency, I don’t kknow. There’s certainly no Switching power supply there…..(other than the mains rectifier bridge which is sometimes construed as a switching device)
Concur that this is a Differential mode issue being converted to CM by the cap,
Thanks, this is groundbreaking, because if differential mode nose can be converted to common mode noise via a capacitor, then the reverse must also be true…and if it is , then that’s great , because we’ rather use diff mode filters than common mode filters, because diff mode filters are easier to do as SMD only.
Sounds like you had a differential mode problem on th phase,
Thanks, surely a differential mode problem, by definition, would manifest itself equally on phase and neutral (I’m assuming by “phase” we both mean “live”)
There seems to be a multiple concurrence that as far as common mode noise is concerned, capacitors have two very distinct functions…
1….They sometimes have a filtering effect, as in the capacitor of an LC filter
2…They sometimes have no filtering effect, but act so as to “channel” the noise to different places.
Is this true?