hi all :)
getting all my parts together for my next project :D and looking for variable caps to tune the tank circuit. i have scavenged a few TVs but they only have small ones.
looking for 100-400pf or so.......not sure the going prices ???
i was also thinking of getting a ganged one maybe 2 or 3 and wire them up in series to increase the max voltage........has anyone tried that ???
even old appliances that i could scavenge them out of would be a great help ???
I'm in Australia
thanks ;D
you could always find somebody with a CNC mill and have one made for you.
On ebay you can find some:
http://cgi.ebay.co.uk/2-Gang-Variable-Air-Capacitor_W0QQitemZ150393976910QQcmdZViewItemQQptZUK_BOI_Electrical_Components_Supplies_ET?hash=item23042df84e
http://stores.shop.ebay.com.au/KW-TUBES_Variable-capacitors_W0QQ_dmdZ2QQ_fsubZ7QQ_sasiZ1QQ_sidZ17107114QQ_trksidZp4634Q2ec0Q2em322
rgds, Gyula
Quote from: telluric42 on February 01, 2010, 11:09:30 PM
hi all :)
getting all my parts together for my next project :D and looking for variable caps to tune the tank circuit. i have scavenged a few TVs but they only have small ones.
looking for 100-400pf or so.......not sure the going prices ???
Unfortunately an
American do-it-yourself electronics magazine (Popular Electronics?) had an article many years ago of how to hand-build 365 pF broadcast band radio variable caps from simple and available parts.
Is there a large library near your residence that has back issues of electronics magazines? Especially English ones? The English are avid tinkerers.
--Lee
Very old car radios also had them - in fact any old radio like 50's or before probably will have them if you can find them.
Hi Folks,
If you are willing to build, here are some links how to make variable caps:
1) http://www.eham.net/articles/5217
and a working link mentioned in the above link: http://www.mydarc.de/dl5dbm/varce.pdf
2) for higher value capacitors (1000pF): http://brneurosci.org/capacitor.html
3) further info on sources for buying: http://www.standpipe.com/w2bri/source.htm
4) a short video on a homemade one: http://www.youtube.com/watch?v=_uPwJp_rxRg
rgds, Gyula
Hey all.
The caps are simple to make.
I made one out of some aluminium sheet and a dowel.
It works better than the ones from old radio's... ;D
I took the dowel and cut slots in it, then glued the 1" sq bits of ally in the slots. With this setup I can also vary the plate spacing as well as the amount of plate overlap.
Here is a clip of my setup powering a wall clock.
http://www.youtube.com/watch?v=LQT01-OA89k (http://www.youtube.com/watch?v=LQT01-OA89k)
Scotty.
Melb, Victoria.