Scr's might not turn off if you give then a square wave. ----- Original Message -----=20 From: "Octavio" To: Sent: Thursday, September 04, 2003 10:08 PM Subject: Re: [EE]: 12VDC to 24VAC help The problem is the controller. It uses triac to turn the valves on and off so I need AC Octavio Nogueira Tato Equipamentos Eletr=F4nicos Ltda (11) 5506-5335 =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D nogueira@tato.ind.br ICQ# 19841898 BASIC Step - O microcontrolador mais f=E1cil do mercado www.tato.ind.br ProPic tools - low cost PIC programmer and emulator http://www.propic2.com =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D -----Mensagem original----- De: pic microcontroller discussion list [mailto:PICLIST@MITVMA.MIT.EDU] Em nome de p.cousens Enviada em: quinta-feira, 4 de setembro de 2003 16:45 Para: PICLIST@MITVMA.MIT.EDU Assunto: Re: [EE:] 12VDC to 24VAC help Most solenoid valves will work with ac or dc As a rule of thumb if it's dc you only use half the ac voltage Peter Cousens cousens@biscit.biz > -----Original Message----- > From: pic microcontroller discussion list [mailto:PICLIST@MITVMA.MIT.EDU] On > Behalf Of Octavio > Sent: Thursday, September 04, 2003 6:11 PM > To: PICLIST@MITVMA.MIT.EDU > Subject: [EE:] 12VDC to 24VAC help > > A picture would be very nice. > The valvules draw around 2A > > Octavio Nogueira > Tato Equipamentos Eletr=F4nicos Ltda > (11) 5506-5335 =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D > nogueira@tato.ind.br ICQ# 19841898 > BASIC Step - O microcontrolador mais f=E1cil do mercado > www.tato.ind.br > ProPic tools - low cost PIC programmer and emulator > http://www.propic2.com > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D > > -----Mensagem original----- > De: pic microcontroller discussion list [mailto:PICLIST@MITVMA.MIT.EDU] > Em nome de Bob Blick > Enviada em: quinta-feira, 4 de setembro de 2003 13:58 > Para: PICLIST@MITVMA.MIT.EDU > Assunto: Re: [EE:] 12VDC to 24VAC help > > > I changed the tag to EE. > > Octavio said: > > I have a irrigation controller and some valvules that > > need 24VAC to operate but I only have 12VDC. > > > > I was thinking about using a pic to drive a Power > > Mosfet H-Brige at 60Hz, I know it will be square > > wave but will this work? Any better idea? > > That'd be 12VAC. > > Easiest would be a transformer with 24V center tap output, ignore the > input. Use two transistors, four resistors and away you go. So you use > it as a three wire inductor. center to +12, collectors to either end. > Make a free-running oscilator. You'll get 24VAC from end-to-end. > > If you need a picture I'll draw one tonight. > > Cheers, > > Bob > > -- > http://www.piclist.com hint: PICList Posts must start with ONE topic: > [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads > > --- > Incoming mail is certified Virus Free. > Checked by AVG anti-virus system (http://www.grisoft.com). > Version: 6.0.512 / Virus Database: 309 - Release Date: 19/8/2003 > > > -- > http://www.piclist.com hint: PICList Posts must start with ONE topic: > [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads --- Incoming mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.512 / Virus Database: 309 - Release Date: 19/8/2003 -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads