high voltage photo flash capacitor charger

[audioguru2]

So I guess you tried my circuit without any current-limiting for the LED. No wonder the transistor blew-up.

 

[steven2]

audio guru i did use current limiting resister but at more than what the led with biult in current limiting resister can tollerate as like in the one transister version capacitor charge indicater the 1/4 watt just burns out so i use 1k at 1/2 watt

 

[steven2]

the latest exsperiment im working on is a simple ring launcher exsperiment so as soon as ive got it all together and if it even flys a few inchers its good enougth to post it then , and powerd from the high voltage photo flash capacitor charger allso electro charger to seem that it can charge them up to , and seem that it works for a short coil gun i hope it works for the ring launcher , which if it works will be the simplest and smallest and shortest ring launcher on the net

 

[steven2]

after ive discharged the charged up non photo flash capacitor into my first coil gun ive noticed that the capacitor still seems to hold a small charge even when its suposed to be discharged , a serch on the net for anserws , and ive come up with some mention about useing a led and resister to indicate this residual charge left in the capacitor , anyhow i dident bother with the resister but i tried touchiong just the bare bones led to the capacitor and it blinked briefly without being destroyed, so the small voltage in it  was now all gone but i wonder why was it there  when i exspected it to be all discharged,

 

[audioguru2]

Capacitors have a parameter called "dielectric absorption" which causes a voltage to develop across them after they have been discharged. Electrolytic capacitors especially have this problem. It messes-up the biasing of transistors or opamp circuits which causes distortion.

 

[steven2]

its funny you should say that audio guru , the only transister in the high voltage photo flash capacitor charger is the irf 540 n channel mosfet and the only ic is the timer  and the rest are just resisters and caps

 

[steven2]

while the latest high voltage photo flash cap charger ,with large 4700uf 250 volts electro, for dishargeing and chargeing, is under construction , here is the latest,  an ignition coil version high voltage photo flash cap charger . now i made a slight modification to the simple ignition coil driver circuit, i added a 0.1uf green cap from pin 4 position on the main board to the bottom neg rail. it is marked as 104,  to convert that look at the  capacitor conversion chert i posted some time ago. now the ignition coil version cap charger was my single arc output type that has no return as it goes to ya finger and i used it to exfoiliate freckels or surface skin . so i modified it to charge capacitors with. now i used the same circuit as i did  with the other version high voltage photo flash cap charger, not the driver circuit but the parts i used to it to be able to charge up the capacitors with now the diode string idea i was trying was no good so i added a 330k 1/4 w resister from the hv out of the coil to the terminal  and from there i threw in the rest  the same as i did with other cap charger well you will see the difference here ,

View attachment 37952

 

[steven2]

here is what it looks like now  . the 330k reister you cant see as the leads are in the way  this unit used to have  a modified high voltage polarity indicater in it , useing diodes rated at 15kv each from microwave ovens , but i took it out to do the leatest modifications,

View attachment 37953

 

[steven2]

in the latest here ive made a few home made pvc 1n4508 diode holders as youll see so theres no crambing or parts on any board

View attachment 37954

 

[steven2]

if you zoom in on the positive output terminal inside the box you may see the 330k 1/4 watt resister. here is the front of the cap charger and the neon is protrudeing out the white pvc pannel peace so ill be modifying that next time so it will be a green charge indicater light , by modifying a few 12 volts power indicater lights and useing a neon inside the globe houseing. ive done this allready and have 2 installed on the other unfinished cap charger that i will post when done

View attachment 37955

 

[steven2]

here are some of the test results;  photo flash caps with there lower uf values seem to take  less time to charge up and the higher the value the longer it takes but the results are rewarding when you short them out and get the big bang , the neon charge indicater gets reallybright when the cap is charged up , and if i charge up my 1200uf 200 volts cap with its protection diode and neon with its resisters the first neon to come on is the one in the charger itself the neon on the cap will take longer to come on with this particular circuit but the one on the unit that comes on at its brightest would be the best one to go by  rarether than waiting for neon number 2 to come on which means i would have to let it charge longer when the first neon comes on  ,untill the neon on the cap comes on but its best to stop the charge when the first neon comes on for the sake of the capacitor so you know ya not over chargeing it to much with this cap charger , now for the power it puts into the caps or current well i use my split diode hydrogen oxygen electrolysisi to test it instead of the fingers , this time chargeing the cap up and dumping the charge into the electrolysis thing dosent make the orange glow and fiz, like the other cap charger dose  but you still get the bang when ya short cap out but if i short cap out after trying it on the split diode electrolysis exsperiment the charge is gone so even if the thing dosent glow orange and fiz, the charge is still going somewhere so ill try it in the day when i can see it better

 

[audioguru2]

Hi Steven,
It looks good.
An NE-2 neon light bulb begins to light with 70V to 90V across it. An NE-2H is a little brighter and needs 90V to 110V. Perhaps you should add an 80V zener diode in series with it so that you will have a more accurate indication that a capacitor is nearly fully charged. ;D

 

[steven2]

thankyou audio guru ill try that as soon as i find out if i can get that zener as i think 75 volts is the highest you can get here at the nearest electronics store

 

[steven2]

anyone planing on biulding this ignition coil version cap charger i just found out it , that the positive output  puts out arcs to ya finger to but somehow when i hook up a capacitor to it it charges up great with no damage  yet as if the cap has an internal resistance  of its own

 

[steven2]

heres a printed circuit board  for the high voltage flyback driver circuit for the next high voltage capacitor charger, i just have to wire up the pots and the timer which runs to the main board from the timer socket board

View attachment 38121

 

[steven2]

the latest high  voltage capacitor charger under construction  is an ignition coil version includeing the capacitor thats 4700uf 250vdc and an scr fireing circuit so when its charged the light will come on  then with the push of a button the charge will be dumped iether into my mini coilgun or other but untill its finsished    ill add pictures here of a relay circuit im working on to be used in a high voltage capacitor charger so all you would have to do is push a button and it will switch on the chargeing circuit for the capacitor for a certain amount of time , pending on where you have the rotary pot switched to ,  now the circuit i collected and made into a printed circuit board version is basically an off after delay relay circuit , and  the circuit runs off a nine volts battery temporarilly and the relay is actually 12 volts and works ok in the circuit so latter ill use a supply voltage 9 volts from a regulater circuit and bleed the input from the main 12 volts lead acid cell battery to power the circuit  for the relay timeing etc etc now the voltage devider i used here has a 1m resister and 3x 1.8m resisters and ive tapped between all then aftyer the 1m resister which runs back to the 1m pot  and with  the 1m pot turned down i timed each response of the relay to each position i switch the rotary pot to and if i use the 1m pot it adds more time to each resister the pot is switched to , im not to good at technicle exsplanationsss but this is the best i can do
now i tested this by runing a wire from  a  12 volts lead acid cell battery , to a large 12 volts electric moter, and the positive from the battery to one of the relay contacts then from the other relay contact to the  moter positive then switched the relay timer to say the position that keeps the motor going for  say 5 seconds till its timeing cycle is up then the moter switches off, now this circuit will be used to switch on the high voltage cap charger for any time i choose then switch it off after the time has ended so the cap will get say 60 seconds or more or less pending on where i switched the pot to  then after say 60 seconds of chargeing the relay will switch it off by isolateing the positive wire to the whole high voltage cap charger . on the resister devider board ive got little decals with the times in seconds on them for each switch of the rotary pot and that dosent include the extra seconds i get when i adjust the main 1m pot.  i did time each test with my watch so i have all the details

View attachment 38350

 

[steven2]

the 2 diodes allready on the board are only 1n4148 diodes and so ill still add a rectifier diode to the relay inputs for the reverse voltage protection

View attachment 38351

 

[steven2]

View attachment 38352

 

[steven2]

by the use of the 1m potentiometer i get an extra 15 seconds of capacitor chargeing before the time runs out and the relay turns off the whole circuit. if i set it for 50 seconds chargeing and set the pot to full i get 65 seconds of chargeing.  without this circuit you may be able to modify it to turn off when the chargeing neon comes on , by use of a light deactivated relay circuit ,  once my tests are completed ill redesign the latter ignnition coil version cap charger on printed circuit board with the extra features , thats includeing the 9 volts regulater to power the timer relay circuit and the ignition coil driver all on the one board

 

[audioguru2]

Hi Steven,
You have made a very nice high voltage system. ;D
Did you know that a 555 timer doesn't need a regulated supply? Its max is 18V so it will work from a 12V supply exactly the same as it works from 9V. Post the timer's schematic again to see if its output resistor needs to be changed with the 3 extra volts. What voltage rating is the relay's coil and what is its resistance?