Hi Jinx,

I would think a std. opto driving a high voltage transistor would be fine.

He says the optos are available at sicom, so if you get stuck I can
shoot down there & get you a couple. (I think they do mail order also
- <www.sicom.co.nz>)

Richard



2009/7/6 Jinx <joecolquitt@clear.net.nz>:
> In Figure 3 here
>
> http://www.rory.co.nz/projects/lighting/beat_strobe.html
>
> the author specifies an H11D1/H11D2 optocoupler, which has a
> Vce of 300V, as described in "Opto-coupler Selection"
>
> None of my usual suppliers have the H11D1 or 2, and AFAICT
> none of their other opto-transistors have Vce greater than 70V. It
> isn't possible to do a quick search because output voltage isn't one
> of the parameters, only isolation voltage and output current. Only
> by downloading all the datasheets
>
> Is there a reason why a MOC3020 opto-triac couldn't be used ?
>
> Or is there an alternative opto > 80V ?
>
> How about a Darlington with a lower voltage opto (eg 4N25 or 4N33
> which I have a few of) and an external high voltage transistor ? I think
> I would need a voltage divider to knock down the voltage across the
> opto's internal transistor. If so, how would this affect the drive for the
> SCR gate through the external transistor ?
>
> TIA
>
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