Hi Edson and others, I have not seen his circuit, but my one would run on AC,although I think I have not actually used it like this. (fet across dc output of a bridge rectifier, ac side of bridge in series with mains.) ----- Original Message ----- From: "Edson Brusque" To: Sent: Monday, February 25, 2002 1:35 AM Subject: Re: [EE]: Switching low-voltage AC > Hello George, > > > I made a reverse dimmer in about 1987 using an irfp450 and a 555. The > > curcuit had bult in current limit so you could short the output and it > just > > shut off until you removed it. Later I used it without the dimmer to limit > > the inrush current in lamps for traffic lights, to improve the life. > > I was a very simple curcuit, just semse the drop across the fet with a > > small bipolar transistor wich then shunted the gate to ground. > >You set a limit to the current that the fet will conduct - then switch it > >off. As the fet is on or off the dissipation is low. > > have you actually seen the circuit proposed by dave? > > The high current protection you are proposing (saddly) will not work > work in this circuit but only on DC ones. > > I've been thinking of a pair of very small resistances between the > MOSFETs sources and the ground, but this will reduce the circuit efficience > and a lot of power will have to be dissipated on the resistors. > > Best regards, > > Brusque > > ----------------------------------------------------------------- > Edson Brusque C.I.Tronics Lighting Designers Ltda > Researcher and Developer Blumenau - SC - Brazil > Say NO to HTML mail www.citronics.com.br > ----------------------------------------------------------------- > > -- > http://www.piclist.com#nomail Going offline? Don't AutoReply us! > email listserv@mitvma.mit.edu with SET PICList DIGEST in the body > > -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body