Hi,

I have a 24V square wave output from a thermocouple module and need to convert it into a 0-5V sq wave so that I can read it on a pic pin.
What is the best way to do this?
Many thanks

 

voltage divider to pot it down
IF not good enough then that signal then to drive the GATE of a FET that is pulled upto 5V

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Once a problem is realised, the rest is just details

 

The simplest solution would be a resistor and 4V7 Zener.

The resistor is connected between the 24 signal and the PIC input and the Zener from the PIC input to gnd. Anode to gnd. The resistor would need to be about 10k to limit the current but also to provide enough current to bring the voltage up towards 4V7.

 

All too complicated :lol:

We're talking about a PIC - PIC's are very well designed, sensible devices!. All you need is a single series current limiting resistor from the 24V to the PIC I/O pin - the PIC protection diodes will clip the input to 5V, and the resistor limits the current. It's designed to work in this way!.

As mentioned in my tutorial at http://www.winpicprog.co.uk/pic_tutorial_extras.htm, the very bottom paragraph.

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http://www.winpicprog.co.uk

 

Yes well that far too sensible. Cant be having that. I am going to petition for PIC's to be scrapped on the basis that they do their job

__________________
Nothing is impossible.
Once a problem is realised, the rest is just details