Re: [Phys-l] "Dehatting" TO-3 bipolars to "create" photosensors

[Brian Whatcott <betwys1@sbcglobal.net>]

Thomas O'Neill wrote:
> BC,
>   About ten years ago when John Hinton, Fred Hoffman and I were at the UVa summer institute for Physics teachers, we created a learning module for fiber optics.  The "transmitter" was an LED which whose lens was drilled out to accept a plastic fiber.  The "receiver" was the exact same TO-3 bipolar transistor with a hole drilled in the case to accept the plastic fiber which was glued to the silicon chip.  
>
> Not surprisingly, five minute epoxy turns out to have about the same index of refraction as lens of the LED and the plastic optical fiber and covered a multitude of construction sins.  
....
> THO
>
> Thomas O'Neill
> Physics Teacher in Residence
> James Madison University
> Shenandoah Valley Governor's School
I see that the spectral photosensitivity of the led is downshifted a 
little from its peak emission spectrum. But enough overlap to make this 
an attractive setup.

BrianW