Analyzing pushbutton switch ADC circuit edge cases

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In an ADC circuit with multiple pushbutton switches, pressing one switch can pull the voltage at the ADC pin to zero, effectively grounding it. This results in no potential difference across other switches, meaning they do not affect the circuit's behavior. The series resistors connected to the switches also have zero voltage across them, leading to zero current flow according to Ohm's law. Consequently, only the first switch influences the circuit, rendering the states of the other switches irrelevant. This understanding clarifies the behavior of the circuit in edge cases involving multiple switches.
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Hi, I'm trying to build a circuit with a varying voltage on the ADC pin depending on which switch is held down. In the circuit below, all 4 switches are held down. I would assume that current flows through all of the different switches, but it only flows through the first switch. Why is that so?
Hi, I'm trying to build an ADC circuit with a varying voltage on the ADC pin depending on which switch is held down.
I have been thinking about the edge case where multiple switches are held down, and what would happen. In the circuit below, all 4 switches are held down. I would assume that current flows through all of the different switches, but it only flows through the first switch. Why is that so? Wouldn't some current flow through all of the different switches?
(please apologize for my very rudimentary electronics knowledge. please don't come at me for not trying to think about this on my own, I have been doing so)

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bremenfallturm said:
I would assume that current flows through all of the different switches, but it only flows through the first switch. Why is that so? Wouldn't some current flow through all of the different switches?
When you press the top switch, the voltage at all other switches become zero, so pressing other switches makes no difference.
 
Baluncore said:
When you press the top switch, the voltage at all other switches become zero, so pressing other switches makes no difference.
Sorry for the rookie follow-up question then, but why is that so?
Is it because the potential at the point where the first switch is connected is 0V after it has been pulled to ground, and there is no potential difference between that point and concequtive points after pulling to ground?
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When you press the top switch, the voltage at the ADC node goes to zero, the ground potential.

The three series resistors, 220R + 500R + 700R = 1420R, then have zero voltage across them, so by Ohms law, the current through them, is 0 / 1420 = 0 amp.

Therefor, there is no resistor current to flow through the three lower switches, even if they were closed. There is no voltage across any of those switches, so their state is not important to the circuit analysis.
 
Thank you! I understand now.
 
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