Not sure what's the wave form looks like, will capture some picture with a oscilloscope when I got time. Funny N. Au Group Electronics, http://www.AuElectronics.com http://www.AuElectronics.com/products http://augroups.blogspot.com/ ________________________________ From: Michael Rigby-Jones To: Microcontroller discussion list - Public. Sent: Mon, November 23, 2009 11:30:39 AM Subject: RE: [EE]Good deals on DC AC inverters. > -----Original Message----- > From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf > Of Harold Hallikainen > Sent: 23 November 2009 16:14 > To: Microcontroller discussion list - Public. > Subject: Re: [EE]Good deals on DC AC inverters. > > These are interesting products, and I'm always amazed at how low cost a > consumer product can be. I think these typically have a flyback converter > that converts the 12VDC to +/-170VDC. They then have an H-bridge that > switches the +/-170VDC out at 60Hz. A rectangular waveform is used with > the duty cycle set so the RMS is 120VAC and the peak voltage is 170V. > Doing all that for $17 is quite a trick! > > Harold Many now use the so-called "modified sine" which is just a three level waveform (+v, 0v and -v). This gives better compatibility with equipment that barfs on a simple rectangular waveform (i.e. almost anything with a transformer). Regards Mike ======================================================================= This e-mail is intended for the person it is addressed to only. The information contained in it may be confidential and/or protected by law. If you are not the intended recipient of this message, you must not make any use of this information, or copy or show it to any person. Please contact us immediately to tell us that you have received this e-mail, and return the original to us. Any use, forwarding, printing or copying of this message is strictly prohibited. No part of this message can be considered a request for goods or services. ======================================================================= -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist