Just a thought, chargers for mobile fones may prove a useful starting point if the ones supplied by Nokia are anything to go by. I know they do not give out 5 volts but they do output a low voltage derived from the 240v mains and the weight precludes the use of a transformer operating at 50Hz. Obviously they have cracked the noise issue as the goods carry a CE mark. I have so far resisted the temptation to break one open. Regards Chris ----- Original Message ----- From: "Glenn West" To: Sent: Monday, September 18, 2000 7:44 AM Subject: Re: [EE]: 5V DC from 220V AC supply without a transformer? > For commercial solution, there switchers designed > for hair-driers that will give you 5V few 100ma from 220. And > will last a long time. Can fit in a plug, footprint is small. > > At 01:14 PM 9/18/2000, you wrote: > >On Sun, 17 Sep 2000, Jinx wrote: > > > > > > I have a timer assembly here that uses transformerless power. The > > > > 680n X2 type capacitor is probably not much smaller than a transformer > > > > and much less versatile, especially as the timer has a VFD, so needs > > > > multiple voltages. > > > > > > > > I think more than 10mA is questionable. > > > > > > My power supply reference book states that 1uF will pass 70mA. The > > > > Joe, this will depend on load resistor. I've built this kind of sources > >up to 150mA but it's not a comercial solution. After a while the capacitor > >will die even is up to 630Vca. > > Vasile > > > > > few supplies I've built that use caps as the dropping element would > > > bear that out. Using low quiescent regulators rather than zeners or > > > 78 series regs will mean a smaller cap. Even a 2u2 isn't all that big > > > and if it's reclaimed from a PSU or monitor board the price is right > > > > > > -- > > > http://www.piclist.com hint: The PICList is archived three different > > > ways. See http://www.piclist.com/#archives for details. > > > > > > > > > >-- > >http://www.piclist.com hint: To leave the PICList > >mailto:piclist-unsubscribe-request@mitvma.mit.edu > > -- > http://www.piclist.com hint: To leave the PICList > mailto:piclist-unsubscribe-request@mitvma.mit.edu > > > -- http://www.piclist.com hint: PICList Posts must start with ONE topic: "[PIC]:" PIC only "[EE]:" engineering "[OT]:" off topic "[AD]:" ad's