Re: Rectifier-LP filter circuit

Spehro Pefhany wrote:
On Sun, 11 Nov 2007 08:33:56 -0700, the renowned Jim Thompson
<To-Email-Use-The-Envelope-Icon@xxxxxxxxxxxxxxx> wrote:

On Sun, 11 Nov 2007 10:26:34 -0500, Spehro Pefhany
<speffSNIP@xxxxxxxxxxxxxxxxxxxxxxx> wrote:

On Sat, 10 Nov 2007 20:40:29 -0500, the renowned Fred Bloggs
<nospam@xxxxxxxxxx> wrote:


[snip]
It's not a rectifier, it's an inverting positive peak detector with gain of 12.1.
Looks like that doesn't it? .. but that's not how it behaves (in
simulation anyway), and not how it functionally has to work.

http://server2.hostingplex.com/~zstoretr/output.gif

The waveform at pin 1 is exceedingly ugly. Looks like it's slew rate
limited.

http://server2.hostingplex.com/~zstoretr/outputa.gif



Best regards, Spehro Pefhany
Methinks it's one big typo.

...Jim Thompson

Or deliberate obfuscation, but it seems to work (in simulation)
regardless. I wonder if it's one of those things where someone fiddled
with something on the bench until it seemed to work satisfactorily.

Anyway, I'm going to start from first principles as usual; just want
to make sure I'm not missing anything important.

I have seen circuits where it was almost like that. One version migrated into another, then another. At the end of the week schedule pressure built up and it was all hastily sent to layout, along with parts in there that no longer had any function. Like a transistor with collector as well as emitter to ground.

--
Regards, Joerg

http://www.analogconsultants.com/
.

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