Helps if I send from the correct account... I am looking for an opto-isolator circuit for roughly 1 Hz to 50 KHz using a minimum of parts. I have been told I will need an amplifier circuit as well to drive the LED in the isolator. I have no personal experience with this component. Any ideas? Kurt --- Ross Technologies Signals Intelligence Division Rosetta Proving Grounds (775) 629-0831 ext. 406