9Vdc to 200-300 Vdc converter

[HarveyH42]

Well, fried a phot-flash board the other day, so figured I'd take a shot at converting it over to 9 Vdc. Pretty sure I smoked the transitor (its house marked so, best I'll be able to figure is whether its NPN or PNP. Anyway, the original seems to be simply a transister, resister, and small transformer.

Anybody have a similar arrangement for 9 volts to 200 or so volts DC.

 

[Papabravo]

What was the input voltage before it was destroyed? How much current do you need at 200 - 300 Volts? Are we charging a capacitor for some period of time and then discharging it through the flash tube?

 

[HarveyH42]

It's the flash out of a disposiable camera, works off 1.5 volts. Origionally a AA size, but C and D cells worked just as well. Apparently, above 1.5 volts doesn't, a 9 volts kills it...

Current... don't know, charge rate on the capacitor not too important. It takes 8-10 seconds off a AA battery. The capacitor is 160uF at 330Vdc. if that helps. Bascally looking for a simple 9volt replacement for the 1.5.

I was going to try gust replacing the transistor, but the old one is house marked, so no specs, but should be able to figure out if its NPN/PNP. Then again, it maybe some other 3 -lead device...

I should get busy and draw a schematic for the flash board, its not real complex, just small (little lazy).

 

[Russlk]

The circuit is working at 1.5 volts, so why do you want to go to 9 volts? you will have to redesign the entire circuit including the coil (transformer?).

 

[HarveyH42]

I have a PIR motion detector that runs off a 9 volt battery, and it will output a 9 volts for about 15 seconds. This is good for 1 maybe 2 flashes. I've had no luck getting these flash boards to work on anything other than 1.5 volt batteries. Tried to drop the voltage with a simple resister, voltage divider, diodes. I fried this flash board with a potentiometer...

Just guessing I fried the inverter transistor, likely the weakest part, can't rule out the transformer, and have no specs on it anyway. Hate to count on the transformer being good, and handling the higher voltage.

Guess I should give a quick overview of this whole project...
A solar panel charges a 9 volt battey pack during the day, then powers the PIR at night.
Neighbor's cats (way too many, 17 last count), the raccon, or the fat (pregnant) opposum triggers the PIR, which fires the flash (will adjust for 2-3 flashes later). Also, a loud "POP" will be heard with the flash.
Blinding flash and loud noise should deter most nighttime visitors, people too...

Everything is going well, except the flash board, and I need to determine how much abuse a piezo-tweeter can stand.

 

[Oznog]

You just need a regulator really. Can an LM317 go down that low? If not you can still drop the voltage with diodes once you have a regulated starting voltage.