P3D Re: Slave Flashes

[Tom Deering <tmd@xxxxxxxxxxx>]

On 7/14/98, Greg Wageman wrote:
>From: charlie hotchkiss <revchas@xxxxxxxx>

>> I had a exquisitely simple, dirt cheap circuit to make slave triggers.

>Or, you could buy yourself a Wein "HS" (Hot Shoe) slave for $30 from B&H

Your definition of "dirt cheap" is not the same as mine!  :^)

An alternative to buying a $30 slave is to make a unit similar to the one
below.  It has only three parts, and looks to cost well under five dollars.


This is a quote from FAQ 17 of the Photo Forum.  Tons of good stuff there.
http://www.isc.rit.edu/~andpph/faq.html

>> I'm looking for a simple schematic for a slave flash control.  I can't see
>> spending $20 for a Vivitar when I'm just going to use the insides anyway.
>
>I made something like this and it works ok. If there is a commercially made
>device that only costs $5 I would suggest thay you buy an already assembled
>and tested synchronizer. :-)
>
>               Low Ohms      High Ohms
>                      ___________________________
>       _______       /    |         |            |
>      |       |     /  ___|____   C |  _______   |
>      |Silicon|    /  |        |    |_|       |  |____>
>      |Solar _____/   | Small  |      |  SCR  |          TO FLASH
>      |Cell   | -     | Auto   |      |       |_______>
>      |       |       | Trans- |      | C106B | A
>      |       |-------| former |------|       |
>       -------  +      --------     G  -------
>
>Most small silicon solar cells should work. Most small audio transformers with
>a resistance of about 8 and 400 ohms should work. The SCR could be something
>equivalent but it should be able to handle 200 or preferably 400 volts between
>its A and C leads. Since a SCR is used the flash needs to connected to it the
>right way, meaning the SCR's output is polarized and it needs to match the
>input
>to the flash. If the flash does not fire with the connections wired one
>way try
>reversing them.

Note: I am guessing the "small auto transformer" in the diagram is a type.
I suspect it should have been "audio transformer".

Good luck,

Tom



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