Power ratio over one

[gyulasun]

Hay Gyula:
Well my old razor-recharging transformer bit the dust. It took 3-volt input into my device, and I ended up rattling my switches to pieces. The lesson I learned is don?t run power to the charging unit in reverse! I checked a couple of dozen different transformers and the one that works the best (as far as resistance) is my new camera recharger! The output is 4 volts and 30mA, DC average, when its hooked to the output coil. I don?t have a clue what kind of circuit is in it but the case is rather flat, vs., the more typical dome type transformers. What to do with the power from there I don?t have a clue. I would think that I would need to temporally store the power before it goes into the driver coil.

About the capacitor, I referred to earlier; I can hook the cap with a diode straight off the output coil terminals. I don?t have any ideas what to do with the charged cap after that.

I might need to charge a battery first and switch batteries as Mr. Krieg suggested. Your ideas would be appreciated. Just a note, Stefan is talking way over my head with the circuits!

Thanks
David

Hi David,

I have drawn a schematics on a "power supply" that I think will serve good in converting the 2-10Hz AC voltage created in your green output coil(s). 

I do not insist on your using the Radio Shack mains transformer I show, you may choose from your choices of your junk box:  the goal is it should have a 110-120V AC primary input winding and a 6 or 12 or 18V AC secondary winding of at least 1 Amper output current capability . And I mean you should have access to its secondary winding connections directly, not meaning it is connected to other components in its original circuit (if it is so, then you must disconnect everything from the secondary coil of your transformer, so that there should be no any unwanted component connected to the secondary, except what I show in my drawing). 
The RS transformer has a center tap on its secondary coil, it means practically it has two 6V windings connected inside in series and the connection point is the Black wire (usually), the 12V is between the two red wires (usually).  I do not know what color the primary coil wires are brought out with, but you can idenfy them by DC resistance metering with your meter: you must find some tens Ohms or higher of primary DC resistance and almost a short circuit (1-2 Ohms) secondary coil resistance.

The full wave bridge can also be replaced with any diode bridge you happen to have: the goal is it must be of at least 1-2 Amper forward current with 20-30V reverse voltage ratings.  If you have 4 individual diodes of similar ratings I will show you how to make the diode bridge instead of this one.

The puffer capacitor has its own polarity marked on its body with either arrows or light color stripe lengthwise: that is its negative side. If you have any other similar electrolytic capacitors like 1000uF or 4700uF etc with at least 16V or higher DC voltage ratings, you can use them of course.

When you are ready with building this circuit, and double checked for correct wireing,  please connect it to your mains output of 120V AC for testing it!  You could load it with anything that consumes around 0.5 - 1 Amper at the measured DC OUTPUT I indicated in my drawing.  Then write what you have found, ok?

Good Luck and if you have any questions, ask.

Gyula

[lionhart]

Hi all,

@Handyguy1

I see what you have created is a mechanical H-Bridge.

When X is down A = Pos & B = Neg, and when Y is down A = Neg & B = Pos.

[gyulasun]

Hi all,

@Handyguy1

I see what you have created is a mechanical H-Bridge.

When X is down A = Pos & B = Neg, and when Y is down A = Neg & B = Pos.

Hi,

Yes, you are right.  Here is some explanation on (an electrical) H-bridge for someone wishes to know more:
http://en.wikipedia.org/wiki/H-bridge

But in fact the function to be performed is doable with a double switch (DPDT) like this:
http://www.nmra.org/beginner/images/reverse.gif   
The goal is to change the output polarity of a DC source at wish/when just needed.

From all these it comes an (electrical) H-bridge could be built to replace the mechanical switches (and the noise will be reduced almost completely with it).  Though to build a high efficiency H-bridge for switching about 1-2V DC at around 0.5-1 Amper switching need is not so easy....

rgds,  Gyula

[handyguy1]

Hay Gyula:

Well, I put together the suggested circuit and the results were not as good as I had hoped. The resistance in the circuit is considerable so the device runs slow. So I used 3-volts as the input, the device was running at a normal speed until I hooked up a load. I tried several different transformers and had the same negative results. Then I revisited my old razor, wondering why the resistance was so low using that recharging circuit.. The problem was that the switch was half on. The razor circuit, under load puts out 1.5-volts at 30mA?s. My camera recharger under load puts out .5 volts and 20mA?s. The best thing about the camera recharger is that there is no slowdown on the device even under load. So I think I will ask my brother-in-law about that circuit. The only problem is that he talks way-way over my head!  Another notable observation I have made is that my Craftsman 19.2 volt recharger doesn?t show any resistance when it is unloaded. When I put the battery in there was only a slight decrease in the device's speed. I believe I can find an old one to tear apart.  I am tinkering with caps right now, but still haven?t stored enough power to operate the device.

So this is where I am right now, any suggestions will be appreciated!

David

[handyguy1]

Hay Wattsup:

Have you had any good results with the reed switches?

David