Subject: [TCRG] RSOH last nigt.
Date: Sat, 14 Apr 2001 13:35:33 -0500 (CDT)
From: Alan Kilian
To: tcrobots@orbis.net (Twin Cities Robots group)
All I can say is 5:00 AM is too late to get to bed.
Brynn brought over all his beautiful tiny circuitboards.
He had 16 boards made at AP Circuits in Canada for $110 (If you subtract
the quick shipping charge and non-standard drill size charge)
They look really nice. mostly surfacemount chips, resistors and everything.
We tried to get two PIN photodiode reciever boards to work, and couldn't
really get either of them to work. PIN diodes in backwards at one point,
Something called Positive ECL (Which I don't understand) One time he
almost burned his finger on the amplifier chip. A bad sign.
Jeff M and Jeff S. had some good talks about how to drive power
transistors with a smaller transistor to get a pile of current to
drive a stepper motor.
Lots of talk about how to cool semiconductors. Is a silpad insulator
and grease the best you can do? How about mica washers? Why do MOSFETS
get as hot as they do? Man 6 Watts doesn't sound like a lot, but it sure
makes a transistor without a heatsink unhappy.
We drove Jeff S's "go cart" around in the dark street. It goes just fine
on 24 Volts, but Brynn rode it at 48 Volts!! Man he was moving.
I'll let Jeff describe it.
Next week I'll try to have a PIN photodiode amplifier built from a
schematic I found on that old InternetWebCommerceEbusiness thingie.
-Alan
