Engineering Electronic circuit with Op-Amp, Switch and Diodes

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The discussion revolves around a circuit involving operational amplifiers (op-amps), switches, diodes, and lightbulbs. Participants clarify the functioning of the circuit, identifying it as an inverting op-amp configuration, where the output voltage changes based on the switch position, affecting which lightbulb lights up. Calculations for voltages at various points in the circuit are debated, with participants confirming Vout values of -8V and +8V for different switch positions. The current flow through the lightbulbs is also analyzed, determining which bulb shines brighter based on their respective resistances. Overall, the conversation emphasizes understanding circuit behavior and the relationship between input and output voltages.
  • #31
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  • #32
No. Both wrong!

You fixed some errors, but introduced more. You keep jumping ahead before your error is sorted out.

Look what you've done to the inputs: you have current going the wrong way from the battery. Current should enter the external circuit from the long side (+) of the cell symbol.
 
  • #33
Let's go back to the sketches here, and just focus on the top one https://www.physicsforums.com/showpost.php?p=3792186&postcount=22

No need for any more sketches. You correctly figured out which diode is conducting. So you know that the circuit is operating, you just need to account for why it does.
 
  • #34
Let's go back to the sketches here, and just focus on the top one https://www.physicsforums.com/showpos...6&postcount=22

No need for any more sketches. You correctly figured out which diode is conducting. So you know that the circuit is operating, you just need to account for why it does.


Because there's voltage?

Look what you've done to the inputs: you have current going the wrong way from the battery
That's because it's an inverter
 
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  • #35
Femme_physics said:
Because there's voltage?

That's because it's an inverter

Uhh :rolleyes:?

Current flows from + to -.
So it (almost) always flows away from the plus pole of a battery (the long line) and it (almost) always flows toward the minus pole of a battery (short line).
Certainly in this case it does.
However, in some of your drawings it does, but in others it doesn't...
 
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  • #37
http://img535.imageshack.us/img535/5793/t2774.gif

Tiny discordant note is your comment "L1 lights more brightly". Why?
 
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  • #38
Because it has more current going through it?
 
  • #39
Femme_physics said:
Because it has more current going through it?
Hmmm <checking back sees they have different resistances>. Quite right! :wink:

Well, almost certainly right. Providing they have equal voltage ratings, the higher current one should be brighter.
 
  • #40
Femme_physics said:
Ok, I think I got it... :)

Yep. :)
 

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