Thread: Maximum current draw through DIO port
View Single Post
  #20   Spotlight this post!  
Unread 10-03-2015, 16:45
jbernardis jbernardis is offline
Registered User
FRC #1403
  
Join Date: Sep 2014
Location: United States
Posts: 7
jbernardis is an unknown quantity at this point
Re: Maximum current draw through DIO port
Actually I've been doing my figuring based on 5v, but I'm pretty certain these ports operate at 3.3v. So if my transistor has a voltage drop of 0.7v, then to achieve ~2ma I need a smaller resistor than the 2k I have in mind. Based on 3.3, the voltage across the resistor would be 2.6v, so using a 1K resistor instead would limit current to ~2.6ma which is in the ballpark.