Hi Declan, That this kind of device did not have a mains filter is not extraordinaly. My cleaner has neither. So the ultra sonic wave is modulated by the 100 Hz half cycles of the mains. I do not know wether this has any effect on the cleaning capacity. At least this saves space under the can. But adding a filter can perhaps change the dissipated power of the power amplifier/oscillator. So, be carefull!
Harry > > Well, I did the tests and am reporting back. We can argue about it later > > 1. BU225s were worse than BUX80s (i.e. more noise) > > 2. They wiped out the medium wave (560 -1600khz) and did not have the > more limited effect of the BUX80s which notched out local stations and > then just annoyed on the rest of the waveband > > 2. Moving mains point did not solve the problem. It reduced it. > > 3. Moving to Battery power more or less did solve it. The radio became > quite understandable, with noisy patches when the ferrite rod in the > radio was end on to the interferance. So it was directional. > > This seems to confirm > > a. That transistor equivelants were a bad idea > b. That the majority of the noise is coming through the mains. > c. That a mains filter might have been a good idea after all. > > /knocks himself on the head > > BTW, These diodes are a mains full wave rectifier, but have NO > electrolytic smoothing it. That's pretty unusual on a single phase. > That's where I'll start. I know, I know, electrolytics are useless at > hf, but it might keep the voltage up across those diodes. > > -- > > With best Regards, > > > Declan Moriarty. > -- > Author: Declan Moriarty > INET: [EMAIL PROTECTED] > > Fat City Hosting, San Diego, California -- http://www.fatcity.com > --------------------------------------------------------------------- > To REMOVE yourself from this mailing list, send an E-Mail message > to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in > the message BODY, include a line containing: UNSUB CHIPDIR-L > (or the name of mailing list you want to be removed from). You may > also send the HELP command for other information (like subscribing). > -- Author: H.C. Croon INET: [EMAIL PROTECTED] Fat City Hosting, San Diego, California -- http://www.fatcity.com --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB CHIPDIR-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
