No power required..!!
« on: August 03, 2004, 05:19:51 PM »
Gentlemen,
I've just built an (ahem) op amp and it passes a sine beautifuly "without power".......Is this the norm?  Or have I just made a scientific breakthrough?

Ayethengyaw
peter
http://www.lazpro.com
I reserve the right to not sell to idiots


No power required..!!
« Reply #1 on: August 03, 2004, 05:26:33 PM »
I was experimenting with with Mosfets and jfets a while ago and i think the jfets passed the signal without power.  Did you use jfets?

No power required..!!
« Reply #2 on: August 03, 2004, 05:27:59 PM »
No.... npns n pnps.
http://www.lazpro.com
I reserve the right to not sell to idiots

rafafredd

No power required..!!
« Reply #3 on: August 03, 2004, 05:31:05 PM »
Strange...

Is the feedback path connected?

No power required..!!
« Reply #4 on: August 03, 2004, 05:32:05 PM »
Ah yes.....that would be it then..... :oops:
http://www.lazpro.com
I reserve the right to not sell to idiots

flyingfader

No power required..!!
« Reply #5 on: August 03, 2004, 07:09:45 PM »
Reading this I remember my first Cathode Folower xperiment, no power but sound :sad:  and no glass and still sound  :oops:  really funny...now

Fly
"Any instrument when dropped will roll into the least accessible corner."

SonsOfThunder

No power required..!!
« Reply #6 on: August 03, 2004, 07:19:17 PM »
Quote from: "flyingfader"
Reading this I remember my first Cathode Folower xperiment, no power but sound :sad:  and no glass and still sound  :oops:  really funny...now

Yup...been the victim of this mistake myself.
The question is: Is there amplification going on?! :green:
I will never forget when I was in college doing a lab entitled "Single Transistor Amplifiers" and one of my lab partners is reading off values on the scope and says, "Wait...how's that possible? We got more voltage coming out than we have going in?" My other lab partner and I about fall over laughing, reminding him of the title of the lab!

Peace!
Charlie
"The sow would rather have her ear than a purse." - PRR

chrissugar

No power required..!!
« Reply #7 on: August 04, 2004, 12:42:42 PM »
If the output level is higher then the input level you discovered a PERPETUUM MOBILE. Congratulations!  :grin:

chrissugar
Christian Mike Sugar
        CMS-LAB

zebra50

No power required..!!
« Reply #8 on: August 04, 2004, 01:08:31 PM »
Whilst we're 'fessing up,

I had an 'inverting op-amp not inverting' syndrome the week.

Checked the wiring....

Removed the batteries - nothing changed.

Removed the op-amp - nothing changed.......


 :oops: too. Glad I'm not the only one that misses the bleedin obvious.
Ribbon microphone services
http://www.xaudia.com
Microphone blog

 

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