Analog inputs?

Hello,
I have problem understanding how analog inputs work. There are several questions for which you might know an answer:

  1. Is the GND at the PWM the same as the GND at analog input (i.e. are they short-circuited)?
  2. Will Analog Input read some value without connecting the +5V pin - will it read with only GND and for example A0?
  3. How much current can 5V-GND use, I would maybe need to use it to power 14 741 op amps?

Thanks

spiralciric:
Hello,
I have problem understanding how analog inputs work.

Clue: They're nothing to do with LEDs or multiplexing.

spiralciric:

  1. Is the GND at the PWM the same as the GND at analog input (i.e. are they short-circuited)?

Yes.

spiralciric:
2. Will Analog Input read some value without connecting the +5V pin - will it read with only GND and for example A0?

If the Arduino is powered with USB or via. the power connector then the +5V pin is an output. You don't need to connect it to anything.

spiralciric:
3. How much current can 5V-GND use, I would maybe need to use it to power 14 741 op amps?

You can usually draw about 500mA from the +5V pin on an Arduino.

Thanks.