Camera slave Flash?

[1Steveo]

Any one know if it is possable to replace the neon lamp in this circut with a Photo diode are a IR photo detector to trigger the strobe for a slave flash?

 

[1Steveo]

I ment neon ( NE2)

I mean replace neon NE2 with a photo trans. are photo diode

Steveo

 

[fat-tony]

Am I just blind? Where is S2?

 

[audioguru]

I would think that the NE-2 ionizes from the bright main flash.

A photo-diode has a very small output signal. A photo-transistor has more output, but turns-on slowly and may not be fast enough.

 

[1Steveo]

SW 2 was replaced by Q4 and NE2. I assume in this circuit when NE2 light up it triggers the gate on Q4.


steveo

 

[Sebi]

Yes. When the C2 voltage higher as 200V, NE2 (neon-lamp,glimm) will conducting, and fired the thyristor. The flash-tube ignited, and suck the energy from C2,so it discharged nearby to zero voltage.Immediately started a new charging cycle up to 200V.... etc.
The TIC type thyristors have sensitive gate, so a photodiode with serial 200V zener can trigger it.

 

[MytyMyky]

I've done this before... The info was actually on the inter net and it triggered the flash pretty well.. I can see that the post is pretty old, so case your still interested, I'll get the link.. can't remember it right now.. heh

 

[Dean Huster]

I don't know if they still make it, but Braun (I'm pretty sure that's who it was) made a little 1-inch cube that you slipped onto the hotfoot of any strobe, turning it into a photo-actived slave. It worked great and with two flashes (the main and a slave), I could light up an entire reception hall. The thing was so cheap that it would have been foolish to build anything from scratch -- and anything I could have built would have had a volume five times bigger than that little cube. Alas, but years ago, that little accessory was stolen from my home .... along with my Nikon F2, three lenses, strobe, extension tubes, etc. Man, do I ever miss that camera.

Dean

 

[MytyMyky]

yeah, it seems that most slave cells are very cheap and work great. i made one for the hell of it, cause i needed it , and cause I was having a hard time getting my hands on one around here.... Anyways, after making the cell I pretty much figured that I would have been bettre off buying one... But it was still fun to make.. heheh


Talk about a loss you had there...xii... I could only imagine....

 

[gmphadte]

take a 400 V SCR with metal case
take/cut off the cap, fix an optic window and u have a LASCR(light activated SCR)

Gajanan Phadte

 

[gmphadte]

Use a solar cell found on cheap calculators. will need some experimenting and a series cap to prevent ambient false triggering

Gajanan Phadte

 

[Rolf]

LACSR substitute...........

Great suggestion, now that LASCR are no longer available.

Thanks
Rolf

take a 400 V SCR with metal case
take/cut off the cap, fix an optic window and u have a LASCR(light activated SCR)

Gajanan Phadte

 

[Rolf]

A photo-diode has a very small output signal. A photo-transistor has more output, but turns-on slowly and may not be fast enough.

I have not had any trouble using photo transistors in slave flash circuits:
https://www.pbase.com/sinoline/digital_slave_trigger