Noob Question -powering CFL from a camera flash circuit

Thread Starter

mauricioscotton

Joined May 31, 2010
10
Hello guys, hows it going?

So, I got this flash roll camera circuit from one of my dad's boxes and I was trying to run flash circuit in order to power up a CFL Bulb..
Ive attached pictures from the circuit with parts description..

I've tried to inject DC-3v in a few inputs(Yellow+Gray wires) and I got AC-660v on lamp output...
But it seems to be incomplete..
Any guesses?

Thanks!
 

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Thread Starter

mauricioscotton

Joined May 31, 2010
10
What do you mean by incomplete? Sounds like the circuit is doing what it's supposed to do.
Yeah, I know it, but there is something missing, like a way to trigger the flash, as there is a LDR on the board and also, there is a mechanic trigger which broke. the trigger goes from the rounded corner close to the black shut into the big solder point located at CAP 203 + RES 10K (green face of the board.)

Plus, there is a few spots with power input, even on the LDR has one.
I'm guessing that this LDR circuit act as a IF, to trigger flash in case of darkness...
 

Thread Starter

mauricioscotton

Joined May 31, 2010
10
Actually, I've asked wrong.

What I've meant was that I'm trying to bypass flash trigger and make it always ON.
I think I've injected in the correct place, but there is something missing as the lamp don't goes on.
I've built this previously, but with a disposable camera, which only has a pure flash module.

I'm sorry.
 

Tonyr1084

Joined Sep 24, 2015
3,675
I'm trying to bypass flash trigger and make it always ON.
You DO realize a "Flash" is just a flash. It's not a flash if it's always on; it's a lamp.

The way (as I understand it) they work is to develop a high potential and keep it resting across the flash tube. With an excitation pulse, usually to a band around the flash tube to initiate a spark, the potential cascades through the flash tube for the briefest period of time. I don't know how long the flash is but it's quite short. Once the voltage stored in the flash capacitor has dissipated the flash is over. Done. Finished. It's not going to light again until the cap has been recharged to a high voltage.

The way they get the high voltage is via (what I believe - could be wrong) is via a charge pump that is driven by a high frequency. A 1.5 volt battery can drive a charge pump and generate the needed 300 volts potential. That's where you get your flash from. To have it "Always on" means conducting a continuous high voltage through that tube. And the arc would possibly be hazardous if it were continuous.
 

Thread Starter

mauricioscotton

Joined May 31, 2010
10
You DO realize a "Flash" is just a flash. It's not a flash if it's always on; it's a lamp.

The way (as I understand it) they work is to develop a high potential and keep it resting across the flash tube. With an excitation pulse, usually to a band around the flash tube to initiate a spark, the potential cascades through the flash tube for the briefest period of time. I don't know how long the flash is but it's quite short. Once the voltage stored in the flash capacitor has dissipated the flash is over. Done. Finished. It's not going to light again until the cap has been recharged to a high voltage.

The way they get the high voltage is via (what I believe - could be wrong) is via a charge pump that is driven by a high frequency. A 1.5 volt battery can drive a charge pump and generate the needed 300 volts potential. That's where you get your flash from. To have it "Always on" means conducting a continuous high voltage through that tube. And the arc would possibly be hazardous if it were continuous.
Yeap, you are 100% correct!
But, I`ve used the same schematic to power up a CFL bulb only...
To make it continuous, you just have to remove the capacitor.
I did this, and on the flash lamp wires, I got 660vac.
But, it seems to be missing something on this particular schematic(from this camera).

Follow up this post and check section 9 of this link: http://www.instructables.com/id/High-voltage-power-supply-for-Nixies-CFL-Neon-Gl/
I did this and it really works as expected.
Now, I was wondering, what is the difference between this two flash circuits?
 

Thread Starter

mauricioscotton

Joined May 31, 2010
10
You DO realize a "Flash" is just a flash. It's not a flash if it's always on; it's a lamp.

The way (as I understand it) they work is to develop a high potential and keep it resting across the flash tube. With an excitation pulse, usually to a band around the flash tube to initiate a spark, the potential cascades through the flash tube for the briefest period of time. I don't know how long the flash is but it's quite short. Once the voltage stored in the flash capacitor has dissipated the flash is over. Done. Finished. It's not going to light again until the cap has been recharged to a high voltage.

The way they get the high voltage is via (what I believe - could be wrong) is via a charge pump that is driven by a high frequency. A 1.5 volt battery can drive a charge pump and generate the needed 300 volts potential. That's where you get your flash from. To have it "Always on" means conducting a continuous high voltage through that tube. And the arc would possibly be hazardous if it were continuous.
You are 100% correct! I understand how it works, as it is like one of those fly killing things...
But, yeah, there is a way of making it constant by removing the capacitor. (on this specific board, injecting 3vdc, I get on the flash wires 660vac).
Please, follow up this post, more precisely at section 9(AA-Type Driven Lights), which shows the same idea that I'm trying to do with this schematic, but with a disposable camera flash: http://www.instructables.com/id/High-voltage-power-supply-for-Nixies-CFL-Neon-Gl/

Now I'm wondering... what is the difference between this schematic and one from a disposable camera? I guess not much...
Can you help with it? I just need to power up it and isolate flash circuit...
 

ian field

Joined Oct 27, 2012
6,539
Hello guys, hows it going?

So, I got this flash roll camera circuit from one of my dad's boxes and I was trying to run flash circuit in order to power up a CFL Bulb..
Ive attached pictures from the circuit with parts description..

I've tried to inject DC-3v in a few inputs(Yellow+Gray wires) and I got AC-660v on lamp output...
But it seems to be incomplete..
Any guesses?

Thanks!
That probably isn't going to run any worthwhile size CFL tube. The flash is a capacitor discharge system that builds up over a period of time and dumps into the xenon tube in a split second. The voltage is wrong too - the flash inverter generates around 300V, I forget what a CFL ionises at but its *MUCH* lower. The secondary on that transformer is grounded on the base of the blocking oscillator transistor, the charging pulses augment the BO feedback. The capacitor charges quickly to start off, but the BO eases back as the augmenting pulses diminish - not a great idea for driving something like a CFL tube which has a "crest factor".

You're better off starting from scratch - a flyback type is easiest, but they tend to blacken one end of the tube. look on americanradiohistory for old hobby magazine archives - they were crammed with fluorescent tube driver projects around the 70s & 80s.
 

sghioto

Joined Dec 31, 2017
1,038
I see the picture in the Instructables link showing the CFL working. He calls it a CFL-light tube and it looks like the base of the bulb has been opened and the ballast removed, wires connected directly to the fluorescent tube, is that right? Otherwise you would just need 120vac to run a standard bulb. As far as the board you have now no way to tell what's missing without a schematic.
Steve G
 

ian field

Joined Oct 27, 2012
6,539
I see the picture in the Instructables link showing the CFL working. He calls it a CFL-light tube and it looks like the base of the bulb has been opened and the ballast removed, wires connected directly to the fluorescent tube, is that right? Otherwise you would just need 120vac to run a standard bulb. As far as the board you have now no way to tell what's missing without a schematic.
Steve G
There is a CFL blog somewhere with a page of various autopsied CFLs and schematics.

http://www.pavouk.org/hw/lamp/en_index.html
 

Tonyr1084

Joined Sep 24, 2015
3,675
Did you say you had one working? I've seen a lot of impossible things on the internet. IN FACT, I can make a CFL glow without attaching ANY wires to it. Won't tell you how though.

Gotta run. Appointment.
 

Thread Starter

mauricioscotton

Joined May 31, 2010
10
I see the picture in the Instructables link showing the CFL working. He calls it a CFL-light tube and it looks like the base of the bulb has been opened and the ballast removed, wires connected directly to the fluorescent tube, is that right? Otherwise you would just need 120vac to run a standard bulb. As far as the board you have now no way to tell what's missing without a schematic.
Steve G
Exactly!
I've forgot to mention that the ballast was removed and only using the tube.
I also got another camera, but still the same result... It seems that I just cant manage to reproduce flash trigger.
OBS: I've already removed Flash capacitor in order to avoid charging and discharging times.
This schematics are almost impossible to find.. :(
 

Thread Starter

mauricioscotton

Joined May 31, 2010
10
Did you say you had one working? I've seen a lot of impossible things on the internet. IN FACT, I can make a CFL glow without attaching ANY wires to it. Won't tell you how though.

Gotta run. Appointment.
:D Actually yes, you can power it up with no wires connection with a Tesla coil (Car Coil / flyback).
I have a few videos doing it with a car coil and a NE555! :D kinda kool...
 

Thread Starter

mauricioscotton

Joined May 31, 2010
10
:D Actually yes, you can power it up with no wires connection with a Tesla coil (Car Coil / flyback).
I have a few videos doing it with a car coil and a NE555! :D kinda kool...

And yeah! I had one that was working... I end up applying to 12v to it, and it shouldn't work anymore...(I'll try to find it and take more pics).
I used to take it to camping... It lasts a lot and its quite bright!:
923114_455776827884610_1077459434_n.jpg
This one, I've used a kodak disposable camera.
 
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