| ??? 05/05/10 07:05 Read: times |
#175696 - You still don't know what my product is? Responding to: ???'s previous message |
Stefan Kanev said:
Hi ,Arun,
I did not understand - what is Your final product. Come on Stefan, i have dedicated many pages/posts describing what my end product is. I repeat - its a 500Watts IR Remote Controlled Light Dimmer with 8 steps of brightness levels, with Complete ON and OFF, unit has three wires; 1)Phase/Hot/Live/Line 2)Neutral 3)Output (to Light), specs are 230VAC,50Hz. If its some UPS supervisor - higher level of safety (of device functioning) is desired. I do not claim that opto is best decision - You will take decision. For such device i think transformer is best , but its really costly and big. I already am using a transformer in my design till now, i want to use SMPS module instead and not puny RC (Capacitive) power supply My friend produces 2-wire dimmer with PIC12f509 , RC powering, triac and infrared receiver, mounted instead wall switch(i'm involved in firmware here). For 8k devices sold, i didn't know any problems with R,C,micro or IR , caused by high voltage spices . Some devices come back with dead triac - but what exactly is reason , hi dont know. (End of life in incandescent lamps is really high power event :-) . You and your friend are very lucky that your product did not catch fire/smoked, Thanks to your country's grid supply - because the RC/Capacitive Powersupply works best "ideally" on Mains (Pure Sinewave) at exact line freq of 50Hz ( or 60Hz for other countries). In our country we have daily power cuts in summers which lasts from 1 Hour to 8 hours a day and people fall back on power inverters and generators, the trouble starts here, we don't know what type of inverter the customer has, it may be a sloppy Square wave type whose 50Hz freq is internally set by a 555 IC and final freq. is not 50Hz and keeps fluctuating. When we calculate the value of the Dropper capacitor in capacitive reactance Powersupply, we assume that the line freq remains "constant" but the above mentioned fact spoils the calculation and finally this type of Power supply fails whenever the line freq.fluctuates As about 25V with 2 optocouplers..... If You use power enough micro with 2..3 timers - You can measure period , length of ON and OFF states and calculate where exactly is zero crossing. And You can do this permanently. Yeah, again i have to change the micro and increase the software overhead @ Erik, i thank you for the appnote but it doesn't show what iam looking for, simple resistor divider with a transistor Regards, Arun |
