Joule Thief

[TheNOP]

theNOP or someone else, If I put 2, 300volt caps in parallel, can I add up what they collect from the bridge to a total of 600v?

no and yes
volts add in series.
capacitance(ex: uF) add in parallel

if your bridge does not output 600volts the caps will simply be filled to the maximum the bridge output.

charging in parallel then changing the caps connections to in series, must not stay connected to the bridge, would give you 2x the bridge output

[jeanna]

no and yes
volts add in series.
capacitance(ex: uF) add in parallel

...
...

I want to see if I can collect 600 volts (should I be so lucky) and not to explode a cap, I wondered if I could use 2 in parallel then add them up separately using a dmm on HV.
That will work won't it?

From your top line, I think I need to put 2 300v caps in series to charge them. So, the rest of your comments mean I should not safely do this?

Thanks

@All,
This is cool,

I took this filter which is similar to the recommended choke type toroid MK1 uses. It comes with 2 19turns coils to be used as a filter.

I left them on this time. In the space between the ends of the wound filter, I wound 3-4T of2 wires split as drawn in this new MK 2x style. So I would count them 7T,7T

This is a blockbuster, I think. Look at this.
With some new understanding of my scope, (thanks to NOP and all the other scopies) I connected the cilp and probe to the ends one side of the filter wires and looked at the frequency on the scope.

It was already at 24kHz and made 3 waves right there. It looked just like this: --v----v----v--
I turned the base resistor down and the waves spread out and when they stopped at one wave  --------v--------,
I checked the resistor. 70 ohm.
the voltage was 41 volts.

so a recap
at 70 ohm R_B
41Volts and one wave is about
24kHz

Untuned the cap had collected 32 or 35 volts.

Then. I tried the resistor the other way- up. the waves got deeper and the voltage was 66-64-65v like that.
The resistor was now at 517 ohm , and next I moved the boundary lines of the frequency counter to be at what looked like exactly one wave 
--|=--\/----|=-\/- so between the 2 vertical bars the frequency is now 45kHz. This is very very cool for some HHO reasons, but the whole thing is so great.

So, if I am correct in what I just did, the results are

45khz
65volts
with 517ohms at the base resistor.

Yes?

Thanks to all the scopies for giving me so very much help and patience, esp theNOP, who was the most unrelenting.

wow,

jeanna

[jadaro2600]

@jeanna, consider using two identical capacitors in series.

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This will cut the voltage across the leads on one in half relative to the outermost leads.  Parallel won't achieve anything except increasing capacitance.


You can test this, of course, just setup an experiment.

This will, of course, cut the capacitance of the whole unit in half due to the reciprocal nature of the setup.  This is only when the capacitors are identical, otherwise, things get more complicated.  Consider this as a voltage drop across multiple elements in series.

Two achieve the same capacitance and twice the rated voltage, you would need two sets of series in parallel.

-||-||-
-||-||-

*edits for content, post was a bit premature

Also, I've noticed that when collecting a capacity large and in the uF range, that elements being powered by that capacitance may flicker.

Perhaps what you need is a high voltage nanofarad capacitor?  I found some in a multipack, 1kv, ~700pF (actual measure)

[jeanna]

@jeanna, consider using two identical capacitors in series.

-||-||-

This is the solution.
Yes, thank you.

This is the reason for my questions:

At some point in this outrageousness, the voltage is going to hurt my meters.
I wanted to have a way to find out how much voltage was in the spikes without doing that.
I am now on the threshold of this,
IF I follow up using this 'filter' and wind the pickup of the MK1 onto it. With 65volts on just the jt coils, I may just get something too high to test.
Blowing a few LEDs is annoying but cheap compared to blowing meters.

So, I have 3 of each size cap from 6 fuji cameras. So, I could be fine if I fill these caps, then measure them.

But, theNOP says if I USE the caps... well,
I won't be using the caps except as a test device.
So the only other thing theNOP says to watch is the bridge itself.

Even then, MK1 is saying he has blown some bridges.

I am OK up to 1Amp on the diodes I have but they do not say anything about volts.
My bridge is good to 600 volts.

@MK1 What have you done to measure 850volts?
At some point we will all need to deal with this, I think.

thank you,

jeanna

[Pirate88179]

@ Jeanna:

Great work!!  Don't quote me on this but my understanding and experience with my DMM's is that higher voltage does not hurt them.  If I exceed whatever scale I am on (in volts) I just get the error message..."1".  Now, checking amps or mA's is another matter entirely.  I am on my 4th fuse on my 2nd best meter on the amps side.  The meter is still fine but those fuses are a pain to find around here.   I have accidentally put over 1,000 volts through my meter and still just got the 1 error code....no harm done.

See what the other guys say that have much more knowledge about this than I but, this has been my experience with DMM's so far. (I have 4 of them now)

Bill