True, but an interesting exercise. ----- Original Message ----- To: "Multiple recipients of list CHIPDIR-L" <[EMAIL PROTECTED]> Sent: Monday, September 01, 2003 5:19 AM
> On Sun, Aug 31, 2003 at 08:19:22PM -0800, Joe enlightened us thusly > > At 12:34 PM 8/30/03 -0800, you wrote: > > > I have not seen them for years. a little line current > > > all > > >the time, so this thing would have to distinguish between a fraction > > >of an amp, and the higher draw when the TV is actually on. > > > > Use a step down transformer in reverse. Put the low voltage side > > (secondary) in series with your load and connect a relay to the high > > voltage side (primary). Use a transformer that has a LOW voltage > > output, say 3 volts, and a current rating similar to that of the > > load that you're monitoring. That should give roughly 3 volts line > > drop to the load being monitored, that shouldn't affect the load. > > The relay needs to roughly match the output (primary side). You'll > > have to play with the ratings and you may need to put a dropping > > resistor in series with the relay to decrease it's sensitivity. The > > transformer should have low voltage output when little current is > > flowing to the load (the load is off). When the load is on and > > drawing appreciable current then the output voltage will rise and > > engage the relay. > > > Just lurking on this thread, I'll throw one more approach. Televisions > use ~200W on, but may exceed one amp in inrush currents. > > Drop a few volts - A few diodes in series or cathode to cathode 3V3 > zeners (5W). Across this put 2 optocouplers in antiparallel with a 10 > ohm resistor in series. A Small bleed resistor will make sure the > optocouplers aren't triggered by the bleed current. > > That's 6 components (2 zeners, 2 optocouplers, 10 Ohms and some bleed > resistor). The trouble with asking is that you have to think all these > different ideas through ;-). > -- > > With best Regards, > > > Declan Moriarty. > -- > Author: Declan Moriarty > INET: [EMAIL PROTECTED] > > Fat City Network Services -- 858-538-5051 http://www.fatcity.com > San Diego, California -- Mailing list and web hosting services > --------------------------------------------------------------------- > 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: Syd Levine \(AnaLog\) INET: [EMAIL PROTECTED] Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- 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).
