Watt's the wattage when used on a PIC?

**grahamg** · - 18th January 2015, 12:24

Why do you not just use a 47k resistor in series with the input pin. The internal diodes in the pic will clamp the input voltage anyway. No need for zeners or voltage dividers.

**Dave** · - 18th January 2015, 15:13

Grahang, How are you going to limit the current?

**LinkMTech** · - 18th January 2015, 16:00

Originally Posted by grahamg

Why do you not just use a 47k resistor in series with the input pin. The internal diodes in the pic will clamp the input voltage anyway. No need for zeners or voltage dividers.

I've used this method too but also included a small filter cap to ground at the input pin for noise.
The DEBUG section of the PBP manual shows this as acceptable where +-25V signals are possible to the input.