@JRE Does your blog cover exactly what ripple is and what it does in a CW multiplier?

@W5VO This is the capacitor I have. We were talking about this capacitor and you brought up something about self healing capacitors. Here's a picture of the capacitor... If it helps at all.

@W5VO The top of the cap can be peeled on the edges. Then the top comes right off. Revealing the 10 MegaOhm resistor in parallel. (This is thr normal parallel connection that everyone is familiar with) that is then connected to "sheeting coils" which is wrapped in cardboard looking like material. It feels like soggy or wet cardboard.

@W5VO Everything is surrounded and soaked in what seems to be mineral oil. The smell is awful and the oil doesn't come off of your clothing and is very hard to get off of your skin. I used a rag to clean a spill. The rag has been drenched in beech, chlorine and any form of cleaning agent I could get. (I made sure nothing was mixed, especially the bleach and chlorine. It can be harmful) The rag still smells terrible, so I threw it away.

@KingDuken Add solder to one end. Heat, pull that end up (just push it up with the tip of the soldering iron.) Raise it up far enough that the tab comes off of the pad and there's no solder connecting it to the pad.

Now heat the other end, and push it off the pad. One tab on the capacitor will get bent, but you can usually mash it back into place.

@JRE I connected the first stage of my multiplier using 1.05 uF caps, with 12 kV diodes. The output voltage is "roughly" 4 kV. I will connect it to my testing rig to calculate the approximated voltage. The calculated ripple voltage is 35.712.

@JRE Current Input is calculated to be 6.26 mA.

@JRE For fun I heated a cup of water to the boiling point, (which at my altitude is 202 degrees Fahrenheit) in under 6 seconds. Once it got cool enough I tasted the water. It tasted like burned metal, but electric at the same time. It's hard to compare to something. It's something one needs to try for themselves to understand.

@KingDuken just touch a soldering iron to each end, and slide it off the pads.

Simultaneously (two soldering irons.)

@ScientistSmithYT that is an oil-filled capacitor. Today it is probably filled with mineral oil, but at one time these were filled with toxic and carcinogenic "Chlorinol" PCB's. This summer a customer sent in some big, exotic vacuum tubes for "repair" which were over 60 years old.

Two were broken; one of these was leaking a slightly yellow-ish, acrid-smelling liquid. I promptly placed everything (including the gloves I was using) into three sets of plastic bags. Nope, not going to die that day.

I wasn't sure if oil capacitors were self healing, or if that's a unique property to a few capacitor types. Basically, when you over volt the dielectric, it punches a hole/crack. In self healing capacitors, you also blow out the metal near the hole, which isolates the damage. Otherwise, you will see increased current through the capacitor as leakage through the new defect.

@jre @rdtsc Thank you. I'll try it out.

@KingDuken Use two irons.

Hi!

I've spent much time writing the question and answer for electronics.stackexchange.com/questions/458448/… (I'll update when I can when I'll have new information). In order to avoid it to be deleted one day because closed, could you maybe check if it could be opened?

Now that it has been edited, I think it's no longer "unclear" what I'm asking, don't you think so? Thank you in advance if you can have a look

I get really concerned when I get the eval board for a "space-saving" 4 x 4 mm IC and it comes with a 25 x 25 x 50 mm heat sink installed.

PS: I don't care about points/rep, but more about the fact it could be silently deleted one day if the policy about roomba changes

@Basj Sorry, I think the answer is still "you do your engineering and you try to do it better than the other guy". We can answer questions about specific problems encountered during a design, but asking how to do a whole design is in the same category as asking us to do your homework for you.

@ThePhoton Which other guy? It might be an english saying (i'm not native speaker) but I don't understand what you mean

@Basj Whichever other guy designed one that you want yours to be better than.

@ThePhoton I don't design step up converters and in no way I'm a competitor of these giant ebay sellers who sell such PCB for 1,00$ shipping included...

I posted this question for learning purposes, to understand how 2V can be transformed into 9V in such a small micro-size PCB

I posted it because I was amazed by "this other guy"'s work :)

@Basj You can learn a lot reading the app notes available from TI, Maxim, Analog, ...

You mean the datasheets? Yes, I spent a lot of time reading a TI DAC PDF, it was interesting indeed!

@Basj Really it's not that amazing. You need 1 controller chip, one inductor, two capacitors. There are controller chips down to probably 2 x 2 mm. Inductors down to about the same size. Capacitors down to ~1x2 mm appropriate for this kind of design.

@ThePhoton It's not amazing for you who is experienced about this, but for someone learning like me, it is, thus the question ;)

@Basj App notes. They give more background information about how to design a particular (type of) application, rather than details on one particular chip.

@ThePhoton Oh good to know, I never heard about app notes. I'll try to read one

Is there one in particular you would advise to read?

@Basj I know, but sometimes the answer is, "buy the chip and follow the instructions" and even if you didn't know the answer before you asked, it's not a very interesting question for the main board.

Thanks for your advice, I'll try to find some good app notes!

@Basj Try this one:

analog.com/media/en/technical-documentation/application-notes/…

It's for a really primitive switching regulator controller.

But that means you really have to understand what it's doing to use it.

You'll also want the datasheet for LT1070 to go along with the app note.

Very cool, it seems to explain in detail how buck converters work :)

Would you like to share the link on my question, or should I do it?

@Basj What's cool is you can use that same IC to control buck, buck-boost, boost, flyback, ...

But of course it is a bit too big to fit in a USB connector.

by the way, what's the diff buck vs. boost vs. buck-boost?

oh good to know

there is still one I didn't find: one able to work with a single AA battery, sthg like 1.3 V for example

1.3V to 9V for example

the one I bought works with 2.6V, converted to up to 27V

but with 1.3V, it doesn't work.

@Basj try Webench on ti.com. Enter your input voltage, output voltage, and output current, and it suggests TI chips to use. Remember the AA cell can only deliver so much power, and you can't get more power at the output than you put in a tthe input.

yep! I'll have a look

Thanks!

@Basj Sorry, just tried and it doesn't give anything for 1.3 V in to 9 V out, even with just 50 mA output current.

1.3 is pretty tough --- just barely enough to forward bias a PN junction

that's why we find many 2V to 5V-27V converters for 1$ on ebay, but no 1V to 9V :)

Do you think that's the reason?

@Basj Also the 9:1 ratio. To get 100 mA out, you'd need to put more than 900 mA in, and that's a lot to ask from a battery in a fairly low power application.

yes indeed

typical AA: 1.5v * 2.4 Ah = 3.6 Wh

typical 9V battery: 9v * 0.5 Ah = 4.5 Wh

so more or less we could still use a AA battery instead of a 9V battery (with a little bit less life)

@Basj You might want something like a pack of 4 AAs in 2S2P configuration

yes with 4 AA you can do many things

but the challenge was: would I be able to power a guitar pedal (often 9V powered) with no 9V battery but just one single AA battery?

@rdtsc Thank you, thats very interesting.

@W5VO I don't know either. And I don't know where to look. You already know more about them than I do. As far as healing goes. Thanks. :)