What determines whether a switching supply will properly drive a given load?

Not so. See if you can guess how it generates the HV it needs for the electrostatic field.

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Reply to
Bob Larter
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You don't need a peak-hold meter. You need a DC current probe and a dual-channel storage oscilloscope. Conjecture is no substitute for measurement.

Reply to
mike

Agreed, absolutely. But I don't have a dual-channel storage scope. I'd love to have one of those fency new ones with the LCD (???) displays, but I can't justify the cost, because I don't use it enough. My 25-year-old Philips is gathering dust, as it is.

Reply to
William Sommerwerck

Ok, then use a resistor as a current measurement and your scope in a dark room. You're gonna find it difficult to diagnose a problem if you can't be bothered to even attempt a look at the symptoms.

Reply to
mike

25-year-old

That's a pretty rude thing to say.

The original posting was a question about why most samples of a particular switching supply would not turn on when powering a device whose drain was well below the supply's stated capacity. There was no "problem", as such -- merely an issue of curiosity.

The conclusion was that there was sufficient current inrush to force the switching supply to briefly cut off. I've since found that if I simply leave the supply on, it will eventually "come 'round", though it might take 10 or

15 seconds.
Reply to
William Sommerwerck

Conclusions with no measurement are called conjecture. My pet peeve with newsgroups is the massive amount of baseless input that's presented as FACT.

Problem is that people asking the question probably can't sort the good info from bad advice. If they could, they wouldn't have needed to ask the question.

In a perfect world, all electronic designs would be "robust" and every bit of advice would be good advice. Sadly, it ain't so.

When you substitute part of a system without knowing the issues and experience symptoms you didn't expect, it's time to worry whether it's a good idea.

Conventional wisdom suggests you should beef up the current limit so it doesn't cycle. Be prepared for the possibility that the "correct supply" has soft-limit features that control the startup current and that substituting with one that doesn't have a soft limit may prove very stressful to the system. You might want to implement a softer limit rather than a harder one.

You have a scope...plug it in and find out what's happening. A two-minute experiment is way better than all the baseless conjecture you're gonna get here.

Reply to
mike

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