Dear PICListers : Big thanks to everyone that has taken the time to reply. I'am trying to build a "continuos" control systems. What I mean with this is I want to avoid the use of an H-bridge at the output, I will be using a 10 bits D/A and amplify the signal to produce the 30volt that my DC motor requires. The idea is to show and aply lineal control theory (Laplace-Bode and Z-transform for discrete systems) to the control loop. I will be using a texas instruments TLC5615 serial-10bits-A/D and national LM675 power OP. Suggestions and ideas are always welcome. Eric's page links are not working : >http://www.brouhaha.com/~eric/pic/ -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body