2V/6V signal dropped to TTL levels?

[sirch]

I have a signal that swings between around 2V and 6V and I would like to use this as the input to a micro-controller, is there a simple way of getting the signal down to TTL levels – e.g. 0-5V?

 

[Harald Kapp]

A very simple circuit uses two diodes in series with the input signal plus a resistor (e.g. 1kOhm)

You can use a single 2.7V zener diode instead - note that the zener diode is connected with cathode to "in".

 

[sirch]

Thanks Harald that's great. Why didn't I think of that - inexperience I guess