-- Spehro Pefhany Sent by: pic microcontroller discussion list 10/29/02 09:03 AM Please respond to pic microcontroller discussion list To: PICLIST@MITVMA.MIT.EDU cc: Subject: Re: [EE]: Speeding up a relay - zero crossing detection Sphero Sez: >Oh, why don't you just advance the switching to the relay by a few ms so that switching takes place at the right time? It only has to be *repeatable*, correct? You have more than +/-4msec to play with on a 60Hz line. Good idea. Unfortunately on release the contacts continue bouncing for much too long. With just a catch diode, the release time is plenty long, too, and I am not sure how repeatable it is. I am hoping that releasing the relay more quickly will help the bounce time. If I can't get the bounce time down to 2mS like it is on energizing the relay, then I'm screwed and will have to go to plan B whatever that is. So far I have got the total release time (delay plus bounce) down from 16mS to about 12mS by putzing around putting things in series with the catch diode. If I can shave off another 4mS then I am within my 8mS window that I am shooting for. Also, so far Zeners seem to do the best job. Back to the lab for more experiments! --Lawrence -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads