How to make DIY Variable Capacitors.

Some variable Caps I made from disposable cups and foil. Very easy and quick to make. Good highly progressive range of adjustment. Sorry about my hand blocking out the meter. Another video on the way for those that want to see the meter better. You need watch in HD to read the meters clearly.

If anyone can rate for voltage I would appreciate it. I think they could be good for a few kv?

Thanks for watching.

[EthanDyer]

Super genius idea on the tuning capacitor it’s literally perfect

[rolandberendonck]

Hi mongrel, I still like your Idea. If you want to make a mould of what size and form the foil should be, simply cut one cup; take out the bottom and make one more cut to slice the cylindric shape and there you go.

[MongrelShark]

One of my best creations. Cup caps.
Plastic disposable cups, and tin foil. You can make a variable capacitor with excellent range, and high levels of tuning accuracy. The ones in this video range from 0pf, to 500pf, over 720 degrees of rotation. So better than a pf per deg of turn. The voltage rating on these piticular ones was a bit disappointing. Around 20kv they start to arc across the metal turn stoppers. I have tested non ajustable cup caps, and they are good to around 50kv. The metal stoppers do offer an advantage though. If the regular cap breaks down, the arcing can melt and ignite the plastic cup. Causing fire hazard and destroying the capacitor. With the stoppers in place. Arcing is kept away from the plastic. They can break down over and over, and still work the same. The is no degradation from overvoltage.

[makerj]

Very nice! I really like the welding rod stoppers!

[redoverdrivetheunstoppable]

brilliant!!.. that idea of the stoppers is clever, maybe made with some pieces of plastic instead, no difficulties... i was wondering on how to turn the harness while under hi-v, maybe a plastic wheel on the bottom of the last one while the first is glued to another pair of blank cups (to make a suitable jig) glued as well to some stand or on a base as well, also how to make it less "grippy", those cups are made of a kind of plastic that is really "dry", it may be PVC that is not bad at all for hi-v, maybe some drops of oil....?


i think i'm gonna make it

[KeystoneScience]

This is awesome! Thank you soo much! Variable caps can be pretty pricy so this is a great alternative!

[brentarmstrong]

Thank you this is a helpful video. I have made a small spark gap tesla coil using a stun gun. Your idea using the buckets will work great for it. I've been trying to come up with an easy variable cap to handle the stun gun voltage and that answered it.  

[MongrelShark]

I do non-adjustable ones too. This setup arcs at about 10-20kv, but on the welding rods... so no plastic or foil gets harmed.... Sounds and looks (and feels) a lot like a stun gun when you hook it up to a flyback... will arc on all 4 layers. it crazy! The non-adjustable ones can take a lot of abuse! Especially if you keep the foil down a bit lower from the rim. Rolled over rims are good. when they do arc, the arc will try to follow the roll giving you more distance between plates.

[MongrelShark]

No worries. Good for approx 10-20kv with metal stopper. Much more without. Had some up to 70kv no probs. Look for the thinnest cups you can find. Great for tuning caps etc.

[GianniLaschi]

Nice, good way to make a variable HV Capacitor !!!

[MongrelShark]

Thank you. Been thinking about this one for a while.

[iluzyon]

The one with (welding rods) stoppers...Ingenious! :D

[MongrelShark]

Thank you.They still need a little fine tuning.

[soonersciencenerd]

whats the largest v. cap. you've made?
could you use aluminum tape? I have lots of aluminum tape around!!
good video!

[HighVoltageProjects]

my first HV cap was one like this i made it without wire though, just foil and it took some real beatings 10kv @ 250mA . One of those things i wish i had never thrown away :0(

[nawaz.yaktub_deen-]

Which color goes to position and
What pf does it

[HighVoltageProjects]

mine wasn't adjustable either except for adding or removing cups ;0)

[TempleOfGaia]

How's everyone going here?  Do you think metal spray paint would work in place of the foil?

[johnrobinson]

Not 'picto', rather 'pico'. Otherwise, great stuff.