Jeffrey D. Mathias (jeffrey.d.mathias@worldnet.att.net)
Tue, 23 Feb 1999 07:20:41 -0500
I wrote:
> ...Selinium cells ... have an unpredictable memory ...
Retraction:
I was thinking of Cadmium Sulfide cells as to their memory problems. It
must be my memory that is going. I worked as a research physicist from
1975 to 1986 involving photovoltaic devices. The company grew large
silicon ribbon that was processed into photovoltaic devices (silicon
diodes) which would convert sunlight into electrical power. However
silicon does make the better device, better than cadmium sulfide,
selenium, or any of the other semiconductors.
Hal Faulkner wrote:
> ...The silicon cell, on the other hand generates a very
> small signal which needs to be amplified in order to drive any kind of
> readout. ...
This does depend on the size of the device as the current is directly
proportional to the area. The company's standard device size was 2x4
inches which were then hooked together in arrays. If one diode doesn't
produce enough current, hook up several in series.
> BTW, Paul Horowitz, in the book he co-authored with Winfield Hill, (the Art
> of Electronics, Cambridge University Press) gives some circuit designs for
> using various light measuring devices. No densitometers, however, he does
> discuss in detail the metronome that he designed for Zone VI which changes
> its speed as the intensity of the light source changes. ...
I also have a design for a metronome (included in the guide on my web
page). It is relatively simple and affordable to build. I have used it
for years and it works great. Feel free to build one for yourself, but
don't sell them. Do note that the output from this metronome can also
be feed to a computer.
-- Jeffrey D. Mathias http://home.att.net/~jeffrey.d.mathias/
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