Troubleshooting a Three Input AND Gate Circuit

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Discussion Overview

The discussion revolves around troubleshooting a three input AND gate circuit on a breadboard. Participants explore the connections and functionality of the circuit, specifically focusing on why one of the LEDs does not light up as expected.

Discussion Character

  • Technical explanation, Troubleshooting, Debate/contested

Main Points Raised

  • One participant describes their circuit setup, detailing the connections of inputs and outputs, and expresses confusion about why the second LED does not light up.
  • Another participant inquires whether all necessary input pins are tied high, suggesting a potential issue with the input connections.
  • The original poster confirms that all relevant pins are connected to the positive voltage line but still experiences issues with the second LED.
  • A further question is raised about how the output pin is connected to both an LED and another pin, indicating a possible point of failure.
  • The original poster later reports that they resolved the issue by removing an extra connection that was interfering with the circuit.

Areas of Agreement / Disagreement

The discussion reflects a progression from confusion to resolution, with participants agreeing on the importance of proper connections in the circuit. However, the initial problem remains unresolved until the original poster identifies and corrects their own mistake.

Contextual Notes

Limitations: The discussion does not provide detailed schematics or clarify the specific functions of each pin beyond the basic connections. There is also no exploration of potential alternative causes for the issue aside from the identified mistake.

kenvin100
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Okay, so I am trying to use the breadboard and I have a hard time with a three input AND gate. Guess I can do a schematic

http://imageiso.com/out.php/i17298_3inputandgate.JPG

So in my bread board, I have pins 1 and 2 as inputs..with pin 3 as a LED (output), and I have a jumper connecting pins 3 and 4 cause the result of the first and gate determines if the second AND Gates lights the LED..and I have pin 5 as the input..and pin 6 in another LED..now I connected pin 7 to the ground and pin 14 to +5V..this is the problem: the first and gate works..first LED (on pin3) lights up, but the second one doesnt

I tested everything and I reconnected it to my breadboard..sorry I don't have a picture of it so I am curious why the second one won't light up..Any ideas guys?
 
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So... do you have pins 1, 2, and 5 all tied high?

- Warren
 
yes i did that..its all on high..like on the +ve line..where pin 14 is connect to +5..and i have another wire connected to the power source..well the first led works

and I tried another LED..so I really don't know what I am doing wrong
 
How exactly have you connected pin 3 to both an LED and to pin 4?

- Warren
 
nvm i fixed it.apparently i think i broke the circuit when i added an extra input to pin 4..i just removed that wire and it worked..
 

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