Zero Crossing QuestionJohn, I think you already have the answer to the problem. You stated that "Harris or Intersil IC's work properly regardless of the mains polarity." Some years back I had an issue where another manufacturer's replacement was substituted for a Sprague ULN2003 Darlington Array that I had specified in a design. I was using the ULN2003 to buffer a reset pulse distributed in a system. The other brand was not capable of switching quickly enough in this application. Replacing the ICs with the specified part solved the problem.
I would not waste valuable engineering time resolving an issue that only occurs with one vendor's part. Just one man's opinion, Scott Lacey Simplicate, don't complicate! -----Original Message----- From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of Bouse, John Sent: Monday, January 21, 2002 9:20 AM To: emc-p...@majordomo.ieee.org Subject: Zero Crossing Question Hi Group, Our manufacturing personnel encountered a strange problem: when the mains plug used on a 230V/50Hz equipment that has an internal zero crossing reference integrated circuit (specifically, a CA3059) is reversed (this can occur in countries such as Germany, Italy, France and Switzerland), the zero crossing pulses appear with a 20 millisecond spacing, rather than the expected 10 millisecond spacing. Harris or Intersil IC's work properly regardless of the mains polarity. ON Semiconductor IC's appear to be polarity sensitive. They will produce the proper number of pulses with only one mains polarity. The incorrect spacing of these zero crossing pulses affects the normal operation of the equipment. Has anyone encountered and, hopefully, solved this problem? Regards, John Bouse PKI
