In a message dated 03/07/2001 12:30:01 AM Eastern Standard Time,
mdunn@... writes:
I don't know the exact nature of the failure of sampling
>diodes due to exposure to light but I understand it is permanent. Many
>sampling diode problems are related to improper diode handling techniques.
>When a technician first hears he can't handle them with his fingers, he
uses
>his needle nosed pliers and chips the paint . . . then he realizes what
those
>special plastic tweezers that Tek used to ship with new diode sets are
for .
Wow. I had no idea they were so fragile. I guess LEDs evolved
out of this technology...???
Where I was working in the mid 60s we had some of the first GE plastic
transistors. They were packaged in natural colored epoxy (translucent) and
were released as engineering samples before anyone realized that they were
light sensitive.
Later they came out with a silicon controlled switch in a glass package,
calling it a LASCS. I hooked one up to a battery and bulb and had an
electric lamp you could light with a match. By leaving a connection loose,
you could blow it out. Neat!
I wonder how the problem with the diodes could be non-reversable by
repainting them though (if the paint was opaque to IR).
Mike Csontos
