I'm following an electronics book and I was wondering if someone could help answer some questions for me:
I've got 9 volts connected to a 2.2K resistor going into PIN 2 of the 555 timer. In the book it states:
"The 555 timer receives positive power through the 2.2K resistor, which is 2.2K. Because the input resistance of the timer is very high, the voltage on pin2 is almost a full 9 volts. "
1. Can someone explain to me why the voltage is a full 9 volts because the pin resistance is so high? Wouldn't the 2.2K drop the voltage as well? Why does it seem to not have any effect?
Also, connected to PIN 2 is an open switch connected to a resistor (I don't have the value with me right now) then to ground. When the switch is pressed this creates a voltage divider.
2. I know on paper what a voltage divider is, but if the resistance on PIN 2 is very high will this not interfere with the voltage divider?
I've only seen voltage dividers not connected to anything and on paper.
Thanks for your time,
Cameron.