1.5v to 450v

On a sunny day (Sun, 9 Feb 2014 11:31:47 +0000 (UTC)) it happened Cursitor Doom wrote in :

Charge (450/1.5) capacitors, and then put those in series? (Hello MIT)

Rub it against some plastic foil?

Make a simple one transistor LC oscillator with transformer like this:

Hold a battery in your hand and drag your shoes across the carpet.

Seriously, you need an oscillator and a transformer with/without a voltage multiplier.

Good luck.

Two methods come to mind:

Take the Xenon flash tube circuitry out of an old camera. Grab the schematic for a flash tube driver. They charge a cap up to high voltage. You could probably get even as high as a few 1000 v if you wanted. Then using Jan P.'s oscillator type circuit stack it up to 10's to 20kV if you wnated to get damaging. I don't think the leakage will allow you to get much over that though.

There is one I forgot about. If you can find the article, it describes a hobbyist making a small van de graff(sp?) generator from those 1 inch diameter metal globes. Some guy took two metal globes a plastic tube, rubber band, small motor to run from the battery, and literally made a tiny static generator.

If someone finds that article, please post. It rates right up there with 'way too much time on your hands' but the results also rate up there with "Gee, Mr Wizard."

On a sunny day (Sun, 09 Feb 2014 06:41:41 -0700) it happened RobertMacy wrote in :

v.d. Graaff

thanks for posting, not the article but still interesting. The article Iwas thinking of showed a hand holding the Van de Graaf generator and it stood maybe four inches tall.

Did you calculate the voltage gradients for that shpere? will it really hold 500kV ? maybe.

two inch diameter holds 50kV, so proportionately, 20 inches is required for 500kV. or is that square root ratio? which would mean 6 inch diameter.

The limiting factor is the electic field strength, which is inversely proportional to the smallest radius, so the radius and maximum voltage are directly proportional.

I managed to keep about 200 kV in a van de Graff with a

A standard boost converter (inductor/diode/cap), with BJTs due to low input voltage

If the ratio gives headache, then two in series

Cheers

Klaus

Or a transformer. It's hard to get a boost converter to step up more than 10:1 or so.

There was a WWII sniperscope (IR viewer) that used a watchspring mechanism to close/open a switch contact at 1 Hz. 1.5 volt D-cell, switch, transformer, cold-cathode rectifier, cap. It made something like 1200 volts for the image converter tube.

Some of the cheaper Russian night-vision viewers used a pushbutton; you pumped it manually to charge the cap. Battery, button, transformer, diode, cap.

Get a 1A USB power wall wart. Find the transformer and trace out the three windings: High voltage, low voltage, circuit power.

Pull out the transformer. Get a "very low saturation voltage" transistor like the ZTX1051A. Look up the basic one-transistor one-transformer circuit. Drive current into the "low voltage" winding and use the "circuit power" winding for feedback. Adjust the base bias current until you have just enough power.

The HV side of the transformer will have highly asymmetrical voltage so there's no use for a bridged rectifier. A simple one diode rectifier is perfect. You must use a "fast recovery" diode, not a standard 60 Hz power diode, rated for a minimum of 600V. Reverse the winding if you're not seeing much voltage.

Voltage regulation needs more parts but you haven't said what kind of design you want. The usual feedback is to either apply a negative current to the base of the driving transistor, or lower its bias voltage. A negative current produces smooth regulation but consumes a lot of standby power. Lowering the base bias voltage will probably cause the regulator to cycle on and off, which is more efficient for light loads.

A couple of years back, Walgreens would sell me a single-use film camera, used, for 20 cents. It's not in their "policy manual" but if you sweet-talk 'em...

DC?

Doesn't the inductor cook if the button isn't pressed?

And why does it make 450 volts?

If LVDC is positive, it doesn't work.

Switch arcing and inductor capacitance will very probably keep it from making

Here's my take on it..

LTspice file Attached.

So, what is dI/dT?

Sure.

Totally empty, if it doesn't work.