optotransistors?

[JimRayden]

What about optical transistors? Basically it should be the same as a LDR, Shouldn't it? I want to finish up my Easyvibe but can't find LDR's anywhere, all they have are optotransistors and optocouplers based on them.

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Jimbo

[Coriolis]

Hmm, I don't know about general compatibility between vactrols and optotransistors, but R.G's Neutron filter uses a H11F3 photoFET/LED package (dip 6 I think) as a direct replacement for vactrols- see page 4 of the Neutron pdf here:

http://www.generalguitargadgets.com/diagrams/neutron_filter.pdf

I've been wondering about this too, since vactrols are pricey, and modern optocouplers using transistors or fet's are everywhere, and cheap.
If you do it, and it works, let us know! 

C

[Paul Perry (Frostwave)]

An optical transistor acts like an ordinary transistor, except that the current that normally runs thru the base & is amplified, is supplied by the light. So you get a collector current proportional to the light.
Think there are usually some cheap at Electronic Goldmine. Can't think of any way to use one for a vactrol.

[any]

Just on a sidenote, are there any fun things to do with these opto-resistors?
I've seen them in catalogs and always wondered if they could be usefull in stompboxes...