Quoting Denny Esterline : > I'm looking for sugestions for this bit of analog design. I need to run an > optocoupler, but the end user could connect it to about anything. It could > vary between 12 and 240 volts both AC or DC of unknown polarity. I only need > an off/on indication and if I get pulses from the zero crossings, I don't > mind. > > The best I have at the moment is in the attached schematic, but every time I > look at it I think it's over complicated. Any sugestions? Maybe put a full wave bridge (eg. HD0-06) and halve the rest of it, but I don't see how this is going to work with 240VAC (340V peak) and 100V Darlingtons. I think you'll want more series resistance and some means of dealing with transients on top of the peak voltage (eg. TVS). Best regards, Spehro Pefhany -- "it's the network..." "The Journey is the reward" s...@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist