The standard way to bulk erase tape is to just have a strong 60 Hz magnetic field, then slowly back the tape away from it. The field is often generated using something that looks like an EI transformer core, but without the I part (allowing the flux to escape). Backing the tape away from the coil is a lot simpler than trying to gradually back down the field. Most bulk tape erasers I've seen just have the operator slowly move the tape away. Some have a conveyor belt that passes the tape over the coil, then carries the tape away. One did have a decreasing field. I believe it was still 60 Hz and used phase control to back the field down. Harold On Wed, 21 Feb 2001 13:54:21 +0100 Leo De Palo writes: > Hi PIC'er friend, > > I have been a strange request to build a device able to erase the > video VHS > tape. > > I have in mind to build a coil of 15 cm. of diameter and using a > PIC, to > generate a continuos frequency sweep. > > Passing the tape into this coil, i suppose the tape will be erased. > > Wat do you think about the idea?? > > Wich range of frequency should be used to erase the tape?? > > > Tahnks in advance and regards > > Leo > > -- > http://www.piclist.com hint: PICList Posts must start with ONE > topic: > [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: > ->Ads > > FCC Rules Online at http://hallikainen.com/FccRules Lighting control for theatre and television at http://www.dovesystems.com ________________________________________________________________ GET INTERNET ACCESS FROM JUNO! Juno offers FREE or PREMIUM Internet access for less! Join Juno today! For your FREE software, visit: http://dl.www.juno.com/get/tagj. -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics