I read in !emc-pstc that Richard Jones <[email protected]> wrote (in <001501c30e17$9540bb70$f8edfea9@comp3>) about 'CE and driving LEDs from mains' on Tue, 29 Apr 2003:
> Have 350mA LED(s) in series with 1000mF cap from +ve to -ve within full > bridge rectifier. So far so good. -ve of bridge to mains N. +ve of > bridge goes through a 4.7mF "motor start" rated capacitor to main L. > > Is this legal? > Will it run foul of CE regs. > How do I measure the power efficiency? Don't bother; as you've described it, it won't work. Even if you put the 1000 uF capacitor in parallel instead of series, the LEDs will go up in smoke when you switch on, due to the charging current of the 4.7 uF cap. This type of direct-on-line power supply is practicable only for currents of the order of 10 to 20 mA. If you run LEDs directly from the mains, they must be inaccessible, because the encapsulation doesn't necessarily pass insulation tests, and could be broken in service. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Interested in professional sound reinforcement and distribution? Then go to http://www.isce.org.uk PLEASE do NOT copy news posts to me by E-MAIL! This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: [email protected] Dave Heald: [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
