What to do with a 4000 power supply? That's the question I've been asked countless times since I got it.
Well, I've grown tired of having to think of an answer to that question and here is what I am going to use it for, once and for all:
Click on the images for a screenfull...
That's right 4 kV going right into a red LED. Just kidding of course, it is being current limited (CC mode) to a nice warm and cuddly 10 mA. If I really put 4kV into that LED it would probably blow like no LED has been seen blowing before.
For anyone interested in what goes on inside one of these beasties, here is the first pic on the net of the guts of this particular model (electronics porn warning
):
Yes, everything is big in Texas (and 4 kV power supplies). The mains transformer is the little one on the left side with the 33k resistor across it. You can probably guess what the mother of all power supply transformers in the center does (covered with poured wax too, with little waxcicles that formed on the bottom of it from the pour).
There is a bit of a bodge in there, because I had to replace a 200k 1% (low ppm?) resistor that had gone bad and was screwing up the voltage setting of the hundreds dial:
This is a temporary solution and those aren't just crappy Chinese 1% resistors I soldered in there, they're actually hand picked low ppm resistors (0.1%, +/-15 ppm) that measure almost exactly 200k together (200,005 ohms if my meter is spot on). Unfortunately, together they're only spec'ed at 0.25 W each for a combined 0.5 W load handling ability across the two of them, so I need to replace them with something more substantial. I believe the correct power rating on the rest of the resistors is 1 W, so the search won't be too bad (and the bodge will survive at least for the short term) - I hate entering unobtainium territory with these old supplies. When used properly with a fixed load, there is only about 25 mW flowing through each of them, but I do intend to replace them with the correct part once I place my next order through DigiKey.
Anyways enough of my rant and I hope you've enjoyed this post.
Update:You came in here expecting more (i.e., sparks flying)? Well, here is what 3.2 kV flying through an air gap of about 1/16" (1.5 mm) of air looks like. It took me about a hundred picture attempts at high speed to capture it well:
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