stankus@leland.Stanford.EDU (John Stankus) (03/19/91)
I am desparate need of some high voltage capacitors (4-6KV) 5pF. Since the demise of the vacuum tube nobody seems to make these anymore. Does anyone know of a source for these and other HI-Voltage Capacitors. Thanks John J. Stankus N5PEE Dept. of Chemistry stankus@leland.stanford.edu Stanford University
murray@sun13.scri.fsu.edu (John Murray) (03/20/91)
In article <1991Mar18.194939.1257@leland.Stanford.EDU> stankus@leland.Stanford.EDU (John Stankus) writes: > >I am desparate need of some high voltage capacitors (4-6KV) 5pF. >Since the demise of the vacuum tube nobody seems to make these anymore. >Does anyone know of a source for these and other HI-Voltage Capacitors. I was going to email this, but I thought I'd take the opportunity to state an electronics truism while I was at it: When you can't find something unusual in the surplus and mail-order catalogs, your best bet is to try the 'real' suppliers. Newark Electronics' catalog #111 has on page 273 a ceramic capacitor mf. by Sprague - (60GA series, specifically 60GAQ10) 10pf with a 6,000 WVDC/1000 VAC RMS. This was on page 4 of the Capacitors section. $0.75 at single quantities. If you can't find one that fits your specs exactly in the remaining 73 pages of that section, you could try calling your local Newark supplier and seeing what he can dig up. If you meant 4-6KVAC (should have said!) a closer perusal of the cat. might still help. The Sprague 150GA series, right below the 60GA, has 15,000 WVDC/4500VAC RMS (but Newark only lists down to 100pf - if your Newark supplier can't help, you could always call Sprague) (If this is for RF gear, John, you also didn't mention any frequency requirements...) Disclaimer: no special reason why I picked Newark. I just happen to have their catalog sitting on my desk. >John J. Stankus N5PEE Dept. of Chemistry >stankus@leland.stanford.edu Stanford University -- *Standard Disclaimers Apply*| ---Get Out Of HELL Free!--- John R. Murray |The bearer of this card is entitled to forgive murray@vsjrm.scri.fsu.edu |Himself of all Sins, Errors and Transgressions. Supercomputer Research Inst.| -- D. Owen Rowley
whester@isis.cs.du.edu (William R. Hester) (03/24/91)
In article <1991Mar18.194939.1257@leland.Stanford.EDU> stankus@leland.Stanford.EDU (John Stankus) writes: > >I am desparate need of some high voltage capacitors (4-6KV) 5pF. >Since the demise of the vacuum tube nobody seems to make these anymore. >Does anyone know of a source for these and other HI-Voltage Capacitors. > > >Thanks > >John J. Stankus N5PEE Dept. of Chemistry >stankus@leland.stanford.edu Stanford University John, if checking the local ham swapfests and swap lists fails, then consider making them yourself. Look up the formula for capacitors in the ARRL handbook. You can use small sections of sheet copper, single sided printed circuit board, or even lids from tin cans for the plates. Use window glass to insulate the plates...with the glass extending out from the plates to assure the 6Kv won't arc around the plates. You'll find the dielectric constant for glass to be very good and normal thickness of window glass should give adequate Kv ratings. Another source for factory make caps in this range can be old television receivers... Try stacking six 1.5 KV rated disc ceramic caps in series with good spacing between them. Let's see, six 30pf in series should give about 5 pf that you asked for... Best Luck -- Bill Hester, Ham Radio N0LAJ, Denver CO., USA | N0LAJ @ W0LJF.CO.USA.NA Please route replies to: whester@nyx.cs.du.edu or uunet!nyx!whester Public Access Unix @ University of Denver, Denver Colorado USA (no official affiliation with the above university)