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Dual-Slope Converter Re-invented

s/ECHS(Z).pdf

Oh sorry John, I guess I was a bit terse. We use these caps in the front e nd of an Earth's Field NMR coil. Q of the RCL is something like 100. (mos tly due to R losses in the coil.) But the losses in the cap will effect it too. So 1% dissipation in the cap would drop our Q to something like 50.

0.3% DF would give something like 77... I think. (1.3% loss each cycle.. d o you just add up the loss?)

I also use low DF caps in a Wein bridge oscillator. It was discovered (mos tly by accident) that low DF caps stopped the occasional motor boating (Squ egeing is that the right term?). Don't ask me why.

George H.

Reply to
George Herold
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If you're dealing with active filters I figured out how to cure the effects of dissipation factor in low frequency filters back in the early '70's...

Allowed me to build predictable filters at frequencies well under

100Hz. (I was selling magical filters to a company called Teltone back then.)

Also had a fabulous way to automatically trim center frequency and Q (orthogonally) sand-blasting thick film resistors.

(That I need to find the paperwork on. I remember the basics, but the technique was downright CUTE :-) ...Jim Thompson

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| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
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I love to cook with wine.     Sometimes I even put it in the food.
Reply to
Jim Thompson

PDFs/ECHS(Z).pdf

t end of an Earth's Field NMR coil. Q of the RCL is something like 100. ( mostly due to R losses in the coil.) But the losses in the cap will effect it too. So 1% dissipation in the cap would drop our Q to something like 50 . 0.3% DF would give something like 77... I think. (1.3% loss each cycle. . do you just add up the loss?)

mostly by accident) that low DF caps stopped the occasional motor boating ( Squegeing is that the right term?). Don't ask me why.

Thanks Jim, This is just an LC tank right on the input. The coil is this multi turn jobber, made with litz wire..(It may have something like 1,000 t urns.. not my design.) about the size of a coffee can. (the water sample si ts inside the coil.) With this itty bitty ceramic cap across it. (Well switchable caps you've g ot to tune the front end for the size of the earth's B field.)

George H.

Reply to
George Herold

Thank you.

--
Don Kuenz
Reply to
Don Kuenz

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