[sdiy] Norton & OTA book

[Tim Stinchcombe]

> In searching for more info on the LM3900, I came across a 
> book that looks
> interesting: "49 Easy Electronic Projects for 
> Transconductance & Norton Op Amps" by Delton Horn.
> 
> The table o' contents looks promising (Norton and OTA info, 
> applications like VCOs and VCAs). It looks to be out of 
> print, but Amazon shows half a dozen used copies with prices 
> ranging from $5 to $20US. I've just ordered one, so I'll know 
> in about a week if there's anything interesting in it. Has 
> anyone else seen this book?

Just got me a copy of this book (it was cheap, and it might contain some
ideas). It looks like it has really been thrown together. Here are a few
things I spotted before I stopped looking too hard:

"The conventional operational amplifier has two voltage inputs and a current
output." (Intro, p xi).

"In most practical circuits, positive feedback is used to reduce the gain to
a significantly lower level." (In section 'How an Op Amp works', p4).

Fig 1-2, p5 shows the standard inverting op amp set-up, but no expression
for the transfer function is given.
Page 6 gives the gain equation for the non-inverting set-up, but no circuit
is shown.
Fig 1-5, p7 is the standard differencing set-up: the equation is given, but
unfortunately the resistors are not labelled in the figure.

Fig 2-7, p22, a "block diagram" of the CA3080 is just a repeat of the
equivalent schematic given in Fig 2-2, p17.

OK, so he does say that some prior knowledge of electronics is assumed, but
I'm now primed into expecting the odd error or two in some of the circuits
as well.

Most of the circuits involve only 1 or 2 ICs and a handful of external
components. I was drawn to the "random music maker" (p100), which turned out
to be "the most complex circuit in this book". This consists of a '567 PLL
being used for its VCO; a 3080 used as a S&H; and a '555 to clock the S&H.
The VCO output is sampled and used to control its own frequency, thus giving
a random frequency depending on the exact moment of sampling. That may give
you an idea of the level that it is pitched at (pun entirely intentional).

Still, as I said before, it may contain some ideas.

Tim
__________________________________________________________
Tim Stinchcombe 

Cheltenham, Glos, UK
email: tim102 at tstinchcombe.freeserve.co.uk