Hi Clif:
The steady-state current requirement and the stored charge requirement are independent of each other. These two requirements have been around for a long time. In previous standards, the standards were quite clear that the current and charge are "or'd." >From a technical point of view, if you measure the peak current from a charged capacitor into 2000 ohms, you will find that almost any capacitor, even those very much less than 0.1 uF, charged to more than 2 volts will exceed 0.7 mA peak. So, the requirement makes no sense if the two requirements are "and'd." If I recall correctly, the charged capacitor requirements came from two sources: 1) the pole-to-pole capacitance between the mains (with the switch off) after unplugging the equipment; and 2) the charged capacitor at the HV output terminal of a crt flyback circuit after the tv or monitor has been turned off. Best regards, Rich ----- Original Message ----- From: "Clif Brick" <[email protected]> To: <[email protected]> Sent: Wednesday, November 01, 2006 6:46 AM Subject: 60950 question Greetings all, under 60950:2001, 2.4.2 limits, under limited current circuits... If a device exceeds .7mA peak into 2kohms, is it still acceptable, under 60950, if the signal is non sinusoidal and has a circuit capcitance less than .1uF and a voltage under 450V peak? I calculate my equivelant circuit capacitance at .03uF, the output is from a flyback inductor. My device has an equivelant stored charge of about 10uC, and repeats this charge/discharge cycle about every 5.3mS/188.7Hz. My question is one of understanding whether or not I must AND or OR the seperate clauses in 2.4.2. Any assistance is appreciated. Best regards, Clif Clifton Brick Compliance, Safety and Patent Engineer Invisible Technologies, Inc. 1000 Fuller Drive Garrett, IN 46738 Phone 260-467-5139 Fax 260-467-5103 - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email ______________________________________________________________________
