title: GPIO 3.3v output on raspberry pi 'The channel sent is invalid on a Raspberry Pi'
body: <p>I'm trying to learn how to do some cool things with my Raspberry Pi.  I am trying to run a NMOS transistor with the 3.3V gpio pin on my raspberry pi.  I am pretty sure it is capable of 3.3V output, but i keep on getting an error.  I checked my wiring and my code.  I don't see any problems.  Please take a look at my code below and let me know if you see anything wrong.  Thanks!</p>
  
  <pre><code>import RPi.GPIO as GPIO
  import time
  
  GPIO.setmode(GPIO.BOARD)
  GPIO.setwarnings(False)
  GPIO.setup(12,GPIO.IN, pull_up_down=GPIO.PUD_UP)
  GPIO.setup(17,GPIO.OUT)
  GPIO.output(17,GPIO.HIGH)
  while True:
      input_state = GPIO.input(12)
      if input_state == False:
          #command for running 5v/3.3v output below
          GPIO.output(17,GPIO.LOW)
          time.sleep(3.5)
          GPIO.output(17,GPIO.HIGH)
  </code></pre>
  
  <p>I ran my script using "sudo python myscript.py".  This is the error I keep getting:</p>
  
  <p>GPIO.setup(17,GPIO.OUT)
  ValueError: The channel sent is invalid on a Raspberry Pi</p>