Huh...

Q6 should "never" turn on, since it's hooked to a "current mirror". Q5 and
Q7 Vbe's match Q6's, so it would only turn on if Q7 Vce = 0.

Of course, at Vce = 0, beta is ****, so it's no longer a "current mirror"
either.

That, and as Hobbs said, make this a confusing circuit to anyone who thinks
"Vbe == 0.7V".

I forget if Eber-Molls even models Vbe vs. Ic.

Tim

--
Deep Friar: a very philosophical monk.
Website: http://webpages.charter.net/dawill/tmoranwms

"Jim Thompson" /Snicker
wrote in message ...
Circuit Challenge of the Day

The following circuit...

http://analog-innovations.com/SED/Ra..._Amusement.pdf

is a ramp generator.

It is easy to see how the upper trip point circuitry causes discharge
of the ramp.

But what causes the turn-around at the bottom?

...Jim Thompson
--
| James E.Thompson, CTO | mens |
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I love to cook with wine. Sometimes I even put it in the food.