A
Pull-up resistors are used in electronic logic circuits to ensure that inputs to the arduino settle at expected logic levels if external devices are disconnected or high-impedance. 'Just because you have nothing at all connected to an input pin doesn't mean it is a logical zero.'
https://arduino.stackexchange.com/a/25354
можно обойтись совсем без резистора, воспользовавшись встроенным PULLUP-резистором
https://www.arduino.cc/en/Tutorial/DigitalPins
https://www.baldengineer.com/arduino-internal-pull-up-resistor-tutorial.html
https://arduino.stackexchange.com/a/25354
можно обойтись совсем без резистора, воспользовавшись встроенным PULLUP-резистором
https://www.arduino.cc/en/Tutorial/DigitalPins
https://www.baldengineer.com/arduino-internal-pull-up-resistor-tutorial.html
