Alt-BEAM Archive
Message #01279
To: beam beam@corp.sgi.com
From: Richard Piotter richfile@rconnect.com
Date: Thu, 04 Mar 1999 18:25:42 -0600
Subject: [alt-beam] Re: advanced circuits
> Even the humblest sorry 2-transistor excuse for an SE does not
> require its load to be inductive. It merely needs something with a
> relatively low initial resistance. Try an ordinary low-voltage
> light bulb - you'll find it flashing happily, and it's hardly
> inductive.
Umm, any light that uses a filiment is infact an inductor. every wire itself is
an inductor, however, they are not always great inductors. Open a rao and ook
for the FM inductor coils. They are literaly a few turns of wire! a 2 turn
inductor in my FM radio for FR circuits class can drasticly effect the tuning! I
can place a piece of iron simply near a wire on it to effect it! Don't
underestimte wires and such. If you are in advanced electronics, you'd know that
nearly everything has some sort of resistance, capacitance & inductance! For
example, on a PCB, two traces next to each other have a low pF capacitance. Each
wire acts as an inductor! Infact, you want proof, take a device, such as a TI
graphing calculator and place it right next to an AM radio and it'll pick up
electromagnetic interference generated by the current flowing through the wires
in the calc! The first personal computer (the Altair) had no speaker, but
hobbyists discovered that if they placed a transistor radio on it and pulsed the
data lines the right way, they could generate tones over the nearby radio! ever
notice a pop if a portable radio is near an electrical circuit when it turns on
or off, even though it's not connected! It's cause all wires have some level of
inductance. Even an inductor itself act's as both a capacitor and resistor! a
simple 2 coil transformer has several individual inductances, capacitances, and
resistances! I forgot the counts of each, but it looks like a whole circuit of
it's own, rather than just a transformer. every capacitor has both an internal
resistance, a leakage resistance, and even a slight inductance in the terminals!
a resistor will have a slight inductance, especialy a wire wound. Fortunately
for our brains, the values are usualy so small they can be ignored, except in
ultra precision circuits! My instructor knew a guy from honeywell who's sole job
was to work out those "phantom" values that result! If a guy can be employed
solely for that purpose, you can know it's important! I suppose I'm trying to
say a light bulb is infact and inductor! Hehe! That was long winded! (:
> ---8<---
> > Besides which, we can always take a lession from the software industry
> > and wire up our superlatives in series.
> > Coming soon:
> > The SuperDelux AdvancedVer2++ MegaMasterPhotovoreXtreme17.530c-47
> > [batteries not included]
Hahahahaha!!! (:
Richard Piotter
richfile@rconnect.com
The Richfiles Robotics & TI web page:
http://richfiles.calc.org
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