hi
i want to know the basic circuit for converting a 24volts supply to 5 ttl..
thank you..

 

Hello,

What current will the circuit draw?
Can you post a schematic?

Greetings,
Bertus

 

Do you mean that you wish to power a TTL-level 5v circuit from 24V?

Or do you wish to know if 24V is present or not by testing from TTL level?

 

The LM393 or LM339 work very well in this application. You can configure it as a buffer or as an inverter. You do need to watch your common mode voltages however.