# Arduino Nano resistors on Rx/Tx

**URL:** <https://forum.arduino.cc/t/arduino-nano-resistors-on-rx-tx/624385>\
**Category:** 3rd Party Boards\
**Created:** [December 5, 2019, 6:04am UTC](https://forum.arduino.cc/t/arduino-nano-resistors-on-rx-tx/624385 "2019-12-05T06:04:07Z")\
**Posts on this page:** 1\
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**Author:** ![LarryD](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/larryd/32/215550_2.png) [@LarryD](https://forum.arduino.cc/u/LarryD)\
**Post date:** [December 5, 2019, 6:56am UTC](https://forum.arduino.cc/t/arduino-nano-resistors-on-rx-tx/624385/2 "2019-12-05T06:56:08Z")

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If you were to use D0 as an output in a project (i.e. not as a RX pin), the 1k prevents this pin and the USB TX pin from being damaged. If you think about it, you would have two output pins connected to each other if the 1k was not there.

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