IN THIS INSTRUCT ABLE I AM GOING TO SHOW YOU
(1) HOW A PULL UP AND PULL DOWN RESISTOR WORKS
(2) HOW YOU WILL CONNECT A SWITCH IN A SAFER MODE
(3) AND THEIR APPLICATION
A COMPLETE DETAILS IS ALSO GIVEN IN THE VIDEO DESCRIPTION AS WELL...
Step 1: How a PULL UP an PULL DOWN Resistor Works...
PULL UP AND PULL DOWN WORKS ON A BASIC PRINCIPLE OF VOLTAGE DIVIDER
FOR PULL UP
if the switch is open and considered to be ideal switch ie (resistance = 0) all the voltage is drop across the 10K resister giving 5volt at output
if we closes the switch zero voltage is drop across the switch due to ideal switch condition.....
The PULL DOWN will work in a reverse manner....
Step 2: How to Connect a Switch in a Safe Mode
Mostly used is pull up condition coz
in pull down if we closes the switch some high amount of current will pass through the switch and if the switch is not capable of passing this current then switch will be damaged...
while in the case of pull up resistor will resists some current and we have less chances of damaging the switch
BUT BE CAREFUL WHILE USING THE SWITCH CHECK THEIR CHARACTERISTICS FIRST
Step 3: Application
PULL UP and PULL DOWN resistor used in micro controller to give the logic signal HIGH and LOW
Let say we have arduino and we configured one pin as an input pin so
arduino will not know exactly which signal is at their input pin (high or low) so pull up and pull down will resolve this issue