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Electronic Schematics (alt.binaries.schematics.electronic) A place to show and share your electronics schematic drawings. |
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#1
Posted to sci.electronics.design,alt.binaries.schematics.electronic,sci.electronics.cad
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Circuit Challenge of the Day
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 | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food. |
#2
Posted to sci.electronics.design,alt.binaries.schematics.electronic,sci.electronics.cad
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Circuit Challenge of the Day
Jim Thompson wrote:
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 As the collector current of Q1 drops to zero, its VBEsat drops below the level needed to keep Q4 turned on, due to that 200 ohm resistor dropping 100 mV. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal ElectroOptical Innovations 55 Orchard Rd Briarcliff Manor NY 10510 845-480-2058 hobbs at electrooptical dot net http://electrooptical.net |
#3
Posted to sci.electronics.design,alt.binaries.schematics.electronic,sci.electronics.cad
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Circuit Challenge of the Day
On Fri, 18 Dec 2009 12:46:20 -0500, Phil Hobbs
wrote: Jim Thompson wrote: 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 As the collector current of Q1 drops to zero, its VBEsat drops below the level needed to keep Q4 turned on, due to that 200 ohm resistor dropping 100 mV. Cheers Phil Hobbs Shhhhhh !-) ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | Help save the environment! Please dispose of socialism properly! |
#4
Posted to sci.electronics.design,alt.binaries.schematics.electronic,sci.electronics.cad
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Circuit Challenge of the Day
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 | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food. |
#5
Posted to sci.electronics.design,alt.binaries.schematics.electronic,sci.electronics.cad
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Circuit Challenge of the Day
On Fri, 18 Dec 2009 12:15:25 -0600, "Tim Williams"
wrote: 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 You need to spend some time refining your circuit analysis/design tools. Don't give up your day job ;-) ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | Help save the environment! Please dispose of socialism properly! |
#6
Posted to sci.electronics.design,alt.binaries.schematics.electronic,sci.electronics.cad
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Circuit Challenge of the Day
"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? Years ago I put together a circuit for messing with random inductors, it was based on a bistable and the "off" state was tripped by the rise to saturation current in the driver transistor. The fun part was sensing when the flyback voltage had peaked and was on its way back, to trip the bistable on state. The circuit would be easily recognisable if I could find it - it was a dead bug/bird's nest type thing, but it seems to have vanished without trace - I'm pretty sure I documented the development, but I can't find that either. |
#7
Posted to sci.electronics.design,alt.binaries.schematics.electronic,sci.electronics.cad
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Circuit Challenge of the Day
ian field wrote:
"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? Years ago I put together a circuit for messing with random inductors, it was based on a bistable and the "off" state was tripped by the rise to saturation current in the driver transistor. The fun part was sensing when the flyback voltage had peaked and was on its way back, to trip the bistable on state. The circuit would be easily recognisable if I could find it - it was a dead bug/bird's nest type thing, but it seems to have vanished without trace - I'm pretty sure I documented the development, but I can't find that either. Sounds a bit like a Royer converter. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal ElectroOptical Innovations 55 Orchard Rd Briarcliff Manor NY 10510 845-480-2058 hobbs at electrooptical dot net http://electrooptical.net |
#8
Posted to sci.electronics.design,alt.binaries.schematics.electronic,sci.electronics.cad
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Circuit Challenge of the Day
"Jon Kirwan" wrote in message
... snip I actually like the way it works. I just didn't like the way Jim drew the darned thing. I still don't quite like it -- I'd like to see Q3 and Q4 together, since they're basically an RTL NOR gate (Q4 having a peculiar turn-off voltage). Then invert it with Q2, feed back to Q4 and drive Q1, and you have your driver part, from left to right. Tim -- Deep Friar: a very philosophical monk. Website: http://webpages.charter.net/dawill/tmoranwms |
#9
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Circuit Challenge of the Day
On Fri, 18 Dec 2009 20:07:15 -0600, "Tim Williams"
wrote: "Jon Kirwan" wrote in message .. . snip I actually like the way it works. I just didn't like the way Jim drew the darned thing. I still don't quite like it -- I'd like to see Q3 and Q4 together, since they're basically an RTL NOR gate (Q4 having a peculiar turn-off voltage). Then invert it with Q2, feed back to Q4 and drive Q1, and you have your driver part, from left to right. Well, draw it up the way you'd like. I'd love to see that, if you can afford the moment to do it. Honestly. It might help me do a better job thinking about other things to see a little better about redrafting stuff like this. Anyway, I'd appreciate your shot at it if you feel like trying a hand at it. (I don't agree about your wish for Q3 and Q4, right now, but if you draw it up the way that makes better sense to you I might change my mind about it and learn something.) Thanks, Jon |
#10
Posted to sci.electronics.design,alt.binaries.schematics.electronic,sci.electronics.cad
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Circuit Challenge of the Day
"Jim Thompson" /Snicker
wrote in message ... You need to spend some time refining your circuit analysis/design tools. Don't give up your day job ;-) Tools? What, did you actually think I'd waste a simulation on your silly ideas? ;-) BTW, my "day job" is doing well: I've already sold a number of induction heater kits. :-) See the latest update on my website. Tim -- Deep Friar: a very philosophical monk. Website: http://webpages.charter.net/dawill/tmoranwms |
#11
Posted to sci.electronics.design,alt.binaries.schematics.electronic,sci.electronics.cad
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Circuit Challenge of the Day
On Sat, 19 Dec 2009 00:41:34 -0600, "Tim Williams"
wrote: "Jim Thompson" /Snicker wrote in message ... You need to spend some time refining your circuit analysis/design tools. Don't give up your day job ;-) Tools? What, did you actually think I'd waste a simulation on your silly ideas? ;-) "Silly ideas"? That circuit in I/C form, more than thirty years ago, was in several different automotive ignitions.... used to time dwell. In I/C form the ramp started essentially from zero (I could scale transistor areas). In I/C form it was triggerable rather than continuous, thus no R2, Q3, Q6. That was a circuit I remembered, wanted to use again, pulled it from archive, then couldn't figure out how it worked ;-) Stewing over it, finally it dawned, so I made it up as a teaser to see if anyone could figure it out. So far only one person :-( BTW, my "day job" is doing well: I've already sold a number of induction heater kits. :-) See the latest update on my website. Tim ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | Help save the environment! Please dispose of socialism properly! |
#12
Posted to sci.electronics.design,alt.binaries.schematics.electronic,sci.electronics.cad
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Circuit Challenge of the Day
On Sat, 19 Dec 2009 08:51:01 -0700, Jim Thompson
/Snicker wrote: snip That was a circuit I remembered, wanted to use again, pulled it from archive, then couldn't figure out how it worked ;-) Stewing over it, finally it dawned, so I made it up as a teaser to see if anyone could figure it out. So far only one person :-( Oh, more than one person. But you don't read my posts. So you wouldn't know. Regardless, I enjoyed this thread from you and thanks for adding it. Jon |
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