I heard I can make a really small solar cell from a 2N3055 if I make it open
the case it is and expose the silicon on a light source
is that true? also what is tha output rating if anyone tested it?

"Predator" schreef in bericht
...
I heard I can make a really small solar cell from a 2N3055 if I make it
open
the case it is and expose the silicon on a light source
is that true? also what is tha output rating if anyone tested it?


I guess any silicon can generate a small current when exposed to light. I
think the current depends mostly on the surface area of the silicon.
Even a LED generates a current, but it is very very low (some nA-uA.)
because the die is small.

So just try it out, cut the head from the 2N3055 and connect a multimeter
between B-E / B-C. You will measure some voltage, but when connecting a
small load to it this voltage will drop.

Al

Predator wrote:

I heard I can make a really small solar cell from a 2N3055 if I make it open
the case it is and expose the silicon on a light source
is that true? also what is tha output rating if anyone tested it?

Since the 70's, many photodetectors were made comercially by taking a
small-signal transistor (in standard metal can), cutting the top off,
and fastening a lens at the top.
Then Fairchild designed one that was optimized for photodetection; the
die had a dinky emitter in one corner, making 98% or so of the area as
base-collector for photons; two versions: flat and curved lens; both
plastic (FPT-100 is the only one of them i remember).
These had orders of magnitude greater sensitivity, with similar speed
and slightly better noise characteristics.
A power transistor gives more B-C area, but a lot of the collector
area is wasted by the large emitter.
Too damn bad the FPT-100 is no longer being made...

A glass diode will also generate a small photo voltage ( glass IN4001 to
IN4007 series )

Ray



"Robert Baer" wrote in message
...
Predator wrote:

I heard I can make a really small solar cell from a 2N3055 if I make it
open
the case it is and expose the silicon on a light source
is that true? also what is tha output rating if anyone tested it?

Since the 70's, many photodetectors were made comercially by taking a
small-signal transistor (in standard metal can), cutting the top off,
and fastening a lens at the top.
Then Fairchild designed one that was optimized for photodetection; the
die had a dinky emitter in one corner, making 98% or so of the area as
base-collector for photons; two versions: flat and curved lens; both
plastic (FPT-100 is the only one of them i remember).
These had orders of magnitude greater sensitivity, with similar speed
and slightly better noise characteristics.
A power transistor gives more B-C area, but a lot of the collector
area is wasted by the large emitter.
Too damn bad the FPT-100 is no longer being made...

On Fri, 12 Mar 2004 14:45:19 -0500, "rayjking"
wrote:

A glass diode will also generate a small photo voltage ( glass IN4001 to
IN4007 series )
Ray
And light-dependent leakeage.

Pieter