Posted by Anthony Matonak on November 4, 2005, 1:31 am
Jeff Thies wrote:
> ewitte@hotmail.com wrote:
>> If your interested in a small experiment you can get about 2W out of a
>> $.39 transistor. Keep in mind though you HAVE to heavily concentrate
>> light onto it and heatsink. Because without that its closer to .0003
>> watts. With a cheap mag lens .03 watts. You need a good fresnal lens
>> to do any good. We have been testing with 2N3055 transistors.
>
> How in the world do you do that? 2N3055 are not light sensitive in as
> much as they are enclosed in either metal or plastic!
You pry off the top part of the case to expose the transistor.
This works with any transistor or diode though the amount of
power you get is proportional to the size of the semiconductor.
Big power transistors work best though LEDs have the advantage
of having the semiconductor already exposed to light. There is
even a fellow who uses this principle to make inexpensive solar
trackers using green LEDs for the photosensors.
Anthony
Posted by Duane C. Johnson on November 4, 2005, 1:40 am
Hi Jeff;
> ewitte@hotmail.com wrote:
> How in the world do you do that?
Cut the top off the TO-3 packaged metal
cased units.
When I worked in a components testing lab we
had this cool tiny tool that was a miniature
can opener.
Or, just use a grind stone or file and the top
comes right off. The aluminum ones are easier.
> 2N3055 are not light sensitive in as much as
> they are enclosed in either metal or plastic!
> Cheers,
> Jeff
Duane
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Posted by Steve O'Hara-Smith on November 4, 2005, 6:40 am
On Thu, 03 Nov 2005 19:40:35 -0600
> Hi Jeff;
>
>
> > ewitte@hotmail.com wrote:
>
> > How in the world do you do that?
>
> Cut the top off the TO-3 packaged metal
> cased units.
Be *very* careful some TO3 can transistors contain beryllium
oxide as a heat transfer agent - it is a fine toxic powder that you *really*
don't want in your lungs.
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Posted by ewitte on November 4, 2005, 5:02 pm
> Be *very* careful some TO3 can transistors contain beryllium
> oxide as a heat transfer agent - it is a fine toxic powder that you *really*
> don't want in your lungs.
Mine had a rubbery white substance on it that had to be removed before
doing any testing. With a normal 1" mag lens I'm getting 0.675volts at
up to 50ma. I'm going to be trying it with a 10 inch fresnel lens soon
;)
Posted by BobG on November 5, 2005, 1:38 am
ewi:
I'm getting 0.675volts at up to 50ma.
==============================
Regular cells are .42-.46V at several amps (but they have a lot more
area).
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>> If your interested in a small experiment you can get about 2W out of a
>> $.39 transistor. Keep in mind though you HAVE to heavily concentrate
>> light onto it and heatsink. Because without that its closer to .0003
>> watts. With a cheap mag lens .03 watts. You need a good fresnal lens
>> to do any good. We have been testing with 2N3055 transistors.
>
> How in the world do you do that? 2N3055 are not light sensitive in as
> much as they are enclosed in either metal or plastic!