Voltage Ladder

[matthewh]

I seem to recall from years past something known as a voltage ladder to step up voltage without need of a transformer. It used an oscillator(ex. 555-timer or 110-ac) then an array of diodes and capacitors to step the voltage up. It did not use an inductor or transformer as most DC-DC converters do. Anyone know of an example of a circuit like this?<p>What I want it for is a cheap easy way to step up 4-8 battery voltage to a regulated 9 volt DC ~60ma in a lite package. Perhaps this wont work and I just need to break down and buy the $30 switching DC-DC convertor.<p>Thanks.<p>Matthew<p>[ February 07, 2005: Message edited by: matthewh ]</p>

[dyarker]

What you're looking for is a voltage doubler, or tripler, depending on how many batteries you decide upon. An example is in the 555 Cookbook (my copy isn't handy right now).<p>A Google search on 555 doubler returned this one on first page. It is for -12V out, but by reversing the diodes and capacitors it can be made positive. The addition of a 2N2222 will increase the current capabiliy. By checking more of the search results, you can probably find exactly what you want.

[philba]

I wonder if there is a way to make posts sticky (i.e. stay at the top)? One about searching would be a great candidtate for that. I guess that is one of the downsides to not having a moderator! (all things considered, I'll still take the no-mod route)

[Dean Huster]

My opinion is that "sticky" posts are annoying, as exemplified on this otherwise pretty good board: http://www.electro-tech-online.com/<p>A short and sweet FAQ section might be better. Different things to different people. Remember the original Gernsback board where you had to wait for the entire history (no 30 day or 30 post limit on it) before you could find the little "New Post" button at the very bottom? That was REALLY annoying and was why a lot of us frequent posters made a "Favorites" to that page when it finally came up.<p>Dean

[matthewh]

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr> I wonder if there is a way to make posts sticky (i.e. stay at the top)? One about searching would be a great candidtate for that. I guess that is one of the downsides to not having a moderator! (all things considered, I'll still take the no-mod route) <hr></blockquote><p>Regarding doing a web search before posting. I assure you I did. I searched for voltage ladder quite a bit and only found circuits that used inductors or transformers. Found nothing like I wanted although there were so many hits it may have been buried in there. Following Dale's suggestion I searched for voltage doubler and found all sorts of neat stuff I was looking for.<p>Thanks.<p>Matthew

[Dave Dixon]

Stun Gun projects utilize the same sort of circuit. At least the one I built did many years ago. Adding more and more caps and diodes was a cheap and fun way to get more and more excitement/danger.
Good luck,
Dave N0QOF

[josmith]

Searching can be tricky. I tried searching for "charge pump" and came up with this:http://www.solarbotics.net/library/circ ... _pump.html
among many others.
For what it's worth my vote is NIX on the Stix.

[Ron H]

Do a Google search for "cockroft-walton".<p>[ February 08, 2005: Message edited by: RonH ]</p>

[jollyrgr]

I know what you are wanting in the "voltage ladder". This is a basic circuit based on a circuit called a "voltage doubler". Before I burst your bubble here are some links you will find useful. I will take you through them step by step. <p>555 circuit for voltage doubler oscillator found at this link:
http://www.reconnsworld.com/power_voltdoubler.html<p>(This circuit is slightly different than the others but is the same concept.)<p>
Basic Voltage doubler, tripler, quadrupler circuits. Click on "tripler" "quadrupler"links below each schematic to see progression of the circuits. I know you said you didn't want a coil or transformer but in these links the transformer is simply representing AC voltage. Go here:<p>http://hyperphysics.phy-astr.gsu.edu/hb ... ldoub.html<p>
Good description of how the voltage doubler works is found here:
http://www.reconnsworld.com/power_voltdoubler.html<p>Here is another more detailed site describing this circuit:<p>http://www.tpub.com/neets/book7/27m.htm<p>Looking at the circuit at first is sometimes very confusing but if you see it broken down it makes sense. And note the different ways of constructing this circuit. In the first description the output is across two series capacitors. In the second version of description links the voltage is doubled across a single capacitor.<p>Now to burst your bubble; you can't get high constant currents out of a voltage doubler, tripler, etc. These circuits are useful for things like charging the high voltage on a CRT, producing a zapper for a stun gun, or a spark for some sort of ignitor. There is no free lunch; each time you double the voltage you half the current.<p>Search for "Voltage Doubler" (no quotes) to see many more examples.<p>[ February 08, 2005: Message edited by: Jolly Roger ]</p>