Series Resistor With a Button?

Using Arduino Microcontrollers
1

Hello,

Is it ever considered a good idea to place a resistor in series with a button when you use a pin in INPUT_PULLUP mode? Or does it not even matter?

Thanks,

Mike

2

Never necessary and a waste of resistors!

3

Good to know, thanks!

4

Hmm, what if... incorrect settings on the port like high output and the button pressed?
The 1k resistor cannot hurt.

1 Like
5

Look at the following diagram and check if you really need a resistor in series with a switch when the internal pull-up resistor (Rip) is enabled.
led2-SW

6

I would say definitely not ... assuming that the reading is being taken at the bottom of Rip.

1 Like
7

and possible ESD protection.
The resistor cost only little and adds (little) protection. I wouldn't use this resistor (because I am careless) but adding it is not 100% waste.

8

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