How is this going to result in a different approach to vision, say, and
processing images and using them reflectively - or in a different approach
to controlling movement?
-----Original Message-----
From: Alan Grimes
Sent: Tuesday, August 28, 2012 5:34 PM
To: AGI
Subject: [agi] LM741
om
The elemental unit of an analog computer, akin to an NAND gate, is the
operational amplifier. The canonical opamp is the LM741, which was
introduced in 1968 and is still the standard opamp that everyone uses.
The Japanese have an equivalent part which has pretty much identical specs.
Better parts are now available but engineers usually start out with the
LM741 and chose a different part only if it can't meet their performance
goals. I'm kinda fond of the Jfet input opamps myself but they can be a
bit more fragile.
I did some computer simulations of my father's stereo (made in 1974).
The power amplifiers are basically power opamps made with discreet parts.
You think of an amplifier as conveying a signal from input to output. A
classic tube amplifier does exactly that, sometimes with 6-12 db of
negative feedback.The creepy thing about the simulation was that the
signal appeared to disappear in the middle of the circuit, so I had
trouble even figuring out which wire was even conveying it.
Logically, the signal MUST pass from the collector of Q402 to the base
of Q410. However the voltage swing at that point is many decimal places
below the DC voltage at that point.
But that's the thing. The amplifier doesn't amplify signal! The
difference between the voltages at the input parts, (Q402, non
inverting, Q404 inverting). is in the microvolts range. (Q406 is
basically a 2mA CCS with a 20-30 second time delay), so the input signal
to the amplifier is essentially null.
But the circuit does work. It has a gain defined by R410 and R414.
It is an error amplifier. The brain works in much the same way. Neurons
don't say much to each other unless there is an error signal. The
amplifier's output is your imagination and the input signal are your
sense organs.
Anyway, just a different perspective. =P
--
E T F
N H E
D E D
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