[colug-432] Record from Cassette

[Rick Troth]

On 08/12/2015 05:40 PM, R P Herrold wrote:
> trying to run down the Op Amp Cookbook, I find that was Walter 
> Jung at Sams; Don Lancaster built on it in the (op amp based) 
> Active Filter Cookbook

Op Amps are fun! A truly brilliant invention, made feasible with the
advent of miniaturized semi-conductor based analog electronics. (That
is, they were too expensive to ever construct with vacuum tubes, and a
bit unwieldy when done with discrete transistors ... but chips! yesssss.)

For those who have never played with one, imagine an amplifier with
infinite gain and matched +/- inputs (or a floating, ungrounded input
pair). You control its behavior with your own R/L/C circuit. If you want
a linear gain of exactly 100, you tie "+" to ground, feed the input
through 1K to "-" (thus defining the input impedance), and put a 100K
feedback to "-" from the output. (Okay, so this is inverting, and it's a
gross simplification.)

http://www.electronics-radio.com/articles/analogue_circuits/operational-amplifier-op-amp/op-amp_basic_inv.gif

It's enough to make a software guy wanna get his ham radio ticket and
build something!

-- R; <><