[MinnowBoard] 1.6V output on gpio pin

[Trevor Woerner]

Hi Ken,

On 02/05/16 19:28, Ken Tait wrote:
> The proper way to do this is something like this:
>
>
>
> connect LED_1 to your GPIO pin. You can use almost any small fet. I 
> don't recommend a transistor, if so you will have to put in a pull 
> down resistor to completely turn it off.
>
> Resistor R12 controls the current and therefore the brightness 
> depending upon the led you are using. Different colors require 
> different currents since their voltage drop is not the same. Try not 
> to go below about 120 ohms..10-20ma is sufficient to light most leds.
>
> Ken...hardware designer and software guy :-)

Yours is the solution that worked for me.

I Found the sheet that came with the LEDs I bought. All it says is that 
if my voltage is 5V that I should use a 330 Ohm resistor. Even though my 
voltage is only 3.3V I used a 330 Ohm resistor for R12 anyway.

I don't have any BSS123's or 2N2222's on hand (I should probably get 
some) but I do have BC337's which seem to do the trick as well.

For my R3 I'm using a value of 270 Ohm.

David: it looks like my gpio is still fine since I am able to measure 
3.3V (when it is on) between it and ground with no load.