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Lie Detector Ambiguous

I've seen this simple circuit a few places, I'm not sure who the originator was. Probably been plagiarized by other web sites. So I built one to see how it works.

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It's supposed to be somewhat of a schmit trigger but since the LED has very little voltage change as the current changes, the LEDs don't switch, both stay on in the critical area where there should be only one on. I think I'm gonna try putting some resistance in series with the left LED.

BTW, mine lights the left LED with high resistance, and the right with low resistance, so the left should be green, not red.

Also, the VR1 seems to want to be set to its maximum, so some resistance should be put in series with it. I'm using three 2N3904 NPNs for the transistors. Followups later with more info.

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Reply to
Watson A.Name - "Watt Sun
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A lying lie detector? Say it ain't so!

Reply to
Baphomet

In article , snipped-for-privacy@catskill.net mentioned...

I didn't say that. It's not lying, it's indeterminate, or ambiguous.

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###Got a Question about ELECTRONICS?   Check HERE First:###
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My email address is whitelisted.  *All* email sent to it 
goes directly to the trash unless you add NOSPAM in the 
Subject: line with other stuff.  alondra101  hotmail.com
Don't be ripped off by the big book dealers.  Go to the URL
that will give you a choice and save you money(up to half).
http://www.everybookstore.com  You'll be glad you did!
Just when you thought you had all this figured out, the gov't
changed it: http://physics.nist.gov/cuu/Units/binary.html@@t@h@e@@a@f@f@l@u@e@n@t@@m@e@e@t@@t@h@e@@E@f@f@l@u@e@n@t@@
Reply to
Watson A.Name - "Watt Sun

On Sat, 25 Oct 2003 17:44:53 -0700, Watson A.Name - "Watt Sun" Gave us:

As is believing in any determinations made by such a device.

I'd be willing to bet that an exciting truth can yield the same stimulus as a concealment, falsehood, omission, or lie.

In other words, I have zero faith in such devices. It is good that they are disallowed in courtrooms in the US.

Reply to
DarkMatter

Ah...an ambiguity or indeterminacy detector...much better ;-)

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Reply to
Baphomet

In article , snipped-for-privacy@catskill.net mentioned...

I was trying to KISS. I put a 300 ohm trimpot in series with the left LED, and with it cranked up to max the LEDs still both come on, no discernible improvement. I'm gonna experiment with a transistor CCS in place of R4. A red LED for the 2V base bias, and a trimpot for the emitter resistor to set the current.

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@@F@r@o@m@@O@r@a@n@g@e@@C@o@u@n@t@y@,@@C@a@l@,@@w@h@e@r@e@@
###Got a Question about ELECTRONICS?   Check HERE First:###
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My email address is whitelisted.  *All* email sent to it 
goes directly to the trash unless you add NOSPAM in the 
Subject: line with other stuff.  alondra101  hotmail.com
Don't be ripped off by the big book dealers.  Go to the URL
that will give you a choice and save you money(up to half).
http://www.everybookstore.com  You'll be glad you did!
Just when you thought you had all this figured out, the gov't
changed it: http://physics.nist.gov/cuu/Units/binary.html@@t@h@e@@a@f@f@l@u@e@n@t@@m@e@e@t@@t@h@e@@E@f@f@l@u@e@n@t@@
Reply to
Watson A.Name - "Watt Sun

In article , snipped-for-privacy@catskill.net mentioned...

Well, I thought spice was supposed to _tell_ you what was going on(!) Being that I don't use it, you've seriously weakened my anticipation of using it someday. :-P

I got zapped a while ago, power went out for a half second or so. Damn fires out in the mountains must've caused an arcover of a EHV line. Yesterday it rained ashes to the point where when I walked, little swirls of ash trailed each footstep. Everything outside was covered with it. Probably not good for the paint since it has a high alkali content. Since early this morning it's been smelling like smoke all over, because of the santa ana winds blowing offshore. Weird. I wonder hoe many of those ashes are from burned-up homes?

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###Got a Question about ELECTRONICS?   Check HERE First:###
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My email address is whitelisted.  *All* email sent to it 
goes directly to the trash unless you add NOSPAM in the 
Subject: line with other stuff.  alondra101  hotmail.com
Don't be ripped off by the big book dealers.  Go to the URL
that will give you a choice and save you money(up to half).
http://www.everybookstore.com  You'll be glad you did!
Just when you thought you had all this figured out, the gov't
changed it: http://physics.nist.gov/cuu/Units/binary.html@@t@h@e@@a@f@f@l@u@e@n@t@@m@e@e@t@@t@h@e@@E@f@f@l@u@e@n@t@@
Reply to
Watson A.Name - "Watt Sun

Similar principle to an improbability generator?

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Reply to
Fred Abse

It looks like the 2N3904 loses gain rapidly at low currents. Why not try higher gain transistors or make TR2 into a Darlington pair also. You might also try replacing the transistors with a high gain comparator.

Reply to
Baphomet

I don't get it. I set the circuit up in spice and when I set R2 to 1K and VR1 to 1meg, neither transistor goes on. When I set VR1 to 1K and R2 to

1meg, neither transistor goes on. What the hell is going on?
Reply to
Baphomet

Sheesh! next we'll be digging out the black led's!

Reply to
Mark Jones

You haven't tried them yet? They are GREAT for removing the last few stray photons in a darkroom! ;-)

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Michael A. Terrell
Central Florida
Reply to
Michael A. Terrell

But, but, but.. If there are still stray photons in a dakrroom, then it's not really a dark room, but an almost dark room. :-)

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My email address is whitelisted. *All* email sent to it goes directly to the trash unless you add NOSPAM in the Subject: line with other stuff. alondra101 hotmail.com Don't be ripped off by the big book dealers. Go to the URL that will give you a choice and save you money(up to half).
formatting link
You'll be glad you did! Just when you thought you had all this figured out, the gov't changed it:
formatting link

Reply to
Watson A.Name - "Watt Sun

On Sun, 26 Oct 2003 15:26:17 -0800, Watson A.Name - "Watt Sun" Gave us:

There would be a difference between "darkroom" the noun, and "dark room" the adjective modified noun.

You figure it out.

Reply to
DarkMatter

Geeze! Why do you think they invented black LEDs in the first place? ;-)

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Michael A. Terrell
Central Florida
Reply to
Michael A. Terrell

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