On 11/7/06, Russell McMahon <apptech@paradise.net.nz> wrote:
> God's/my "GSR"* simple switching regulator circuit also features here.
>
>    http://sound.westhost.com//appnotes/an006.htm
>
> And in a constant current version here
>
>        http://sound.westhost.com//appnotes/an003.htm
>
> Over 10,000 of these have been built so far as a 13v to 200V input /
> 12V output power supply for an exercise machine.
>
> Original design was imparted on 24 Feb 2001 at about 10:43am :-)

I believe many more sensors have been sold before your date
using almost exact the same three-transistor design. I've
seen circuit designed by SICK (the leading photoelectric sensor
vendor) before. The application is the same: universal power
supply AC/DC sensors (typically 12V-240VDC and 12/24V-240V AC).
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