I have ArduinoNano (328) connected by USB. I wrote a simple sketch, which reads A0 pin and shows data through Serial. I connected wire to A0 and when I touch wire's other end to "-" electric bus of my breadboard, serial monitor shows me 0. This is correct.
Then other end of wire is free, serial monitor shows about 230-260. Ok.
But then I touched "+" bus of breadboard (connected to "5V out" Arduino pin) serial monitor still shows about 240-260. I measured the voltage on "+" bus by multimeter, it is 4.47 V
Manual for analogRead said, it's range should be 0-1024, so why can't I get more than 260?
my sketch is:
#define ADC A0
volatile int sensorValue; // non-volatile does not matter though
void setup()
{
Serial.begin(9600);
pinMode(ADC, INPUT);
}
void loop()
{
sensorValue = analogRead(ADC);
p("ADC is %d\n", sensorValue );
}