When the button is closed (pressed) it goes from pin 2 to 5V.
So as I learned electricity seeks for the path with the least resistance.
When the switch is closed there is a current flow from ground through the resistor to +5vdc and the input pin 'senses' this +5vdc voltage level and creates a HIGH reading
I've connected a Resistor to 5V and than I meassured the Voltage btw the end of the resistor and ground and I didn't get 5V. So why do I get 5Volts in this button example ?
If he's getting ~3.5 volts downstream of a 508k resistor and 5v upstream it suggests his meter has in internal impedance of ~1m which isn't too hot.....