SEMCORE RC 115 Capacitor Analyzer

[WISCOJIM]

Originally Posted by Tubejunke

Simpson once made and attempt at doing something with that back in the 50s I think. I believe the name was CapacOmeter, but may be wrong.

Capacohmeter

Info here: http://www.byan-roper.org/steve/stev...acohmeter.html



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[Findm-Keepm]

Back in the day when you could easily get 90V Photoflash batteries, we made our own cap tester - two 90v batteries, a VTVM, and a "pinch stand" - essentially a couple of Grayhill 020 component clips. Wired up in series with the VTVM, you could watch the cap charge up - proof it was good. Simple, elegant, and easy, but told you nothing about the value. The first one I built for myself was huge - all 9V batteries, formed up to make a 162V battery, and I just used a piece of copper clad to make two pads to "touch" the capacitor leads.

The Sencore testers aren't difficult to use - each "button" is dedicated, with no duality. I use the leakage test the most, but not for caps - suspect caps just get replaced - it's too easy to just replace the cap. Instead, I use the leakage feature to test neons, Nixie tubes (along with a 12K resistor...) and to measure high resistances like focus dividers and high-megohm (>75Meg) bleeders. It's good to about 3% or so, about what an analog megger would measure to.

The Sencore's low range is good for characterizing variable caps I've pulled from stuff over the years, and I'll admit I've used the ESR test to check a resistor or two. I prefer my Dick Smith tester for capacitor ESR measurements - with the Sencore I have to press a button while holding the leads, not cool when you've got a whole board of electros to check.

Again, I don't test film caps - I just replace them. Panasonic ECQ-E caps from Digi-key are(or were at the time) less than 15 cents each, and an entire set could be recapped for about 5 bucks or so. I don't use the yellow caps for any work - tried them, but one shorted (from new) cap swayed me back to the brand name stuff.

I do some SCR and Triac work, so the SCR250 seemed helpful, and I have all the parts already to build one. Pretty simple to use, and will augment my hobby SCR tester I built from a Popular Electronics article. It doesn't lie, but is limited...

Now to find a cap with a 15Kv, 2nsec transitiion and 4-second recharge.........rail gun, anyone?

[Findm-Keepm]

Originally Posted by WISCOJIM

Capacohmeter

Info here: http://www.byan-roper.org/steve/stev...acohmeter.html



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Is the pulse a steady train of pulses on a one-shot deal?

Philips made a pulse tester good for about 2Kv and up to 60Khz - I used to play with one, connecting 1600V rated TV safety caps at 1200V, with a 9.9 Khz pulse rate, the highest rate above 1Kv. Cheap (read: non-Sprague) safety caps would get warm after a few minutes. At 900V and 15.8 Khz (closest i could get to 15,750...), none of the caps would get warm...

For fun, we'd flash burn foil gum wrappers with the Philips - one pulse at 2KV, and you had a wisp of smoke, and a carbon trail across the foil. I'd love to have had a high-speed camera to film it - you could see the foil buckle as the pulse traveled across it - most likely from the heat.

We used it to pulse test HV cables for airborne fire-control radar pulse-forming networks....I can remember that all the cables I ever tested passed. But sea-level testing proved little - get that cable in an unpressurized aircraft bay, and at altitude, it was a different animal. Arcs, blow outs (where the center conductor burned a trail to the outer jacket) and opens occurred. Hard to do real-world testing. A failed cable showed itself easily - no testing required...