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People who are considering using ths method should be aware of the serious safety problems. In most countries the safety laws require that when using a circuit like this the whole supply and the circuit it powers have to be totally enclosed in two independent layers of insulating material such as plastic shells.
It is not worth your life to save a small amount of funds.
Its a pitty that you upload something that can be found on the microchip web site. Also, there are few more App. notes there that can also help to build a Transformerless power supply.
This circuit is good for currents up to 50mA. They can give higher current but only for short period of time.
I don't know. I think you may be underestimating some of the advantages. Yes you do have to pay more attention to the safety aspect to it and yes you do need to look after the international & domestic regulations BUT I saved $800 on a power supply and 25 pounds worth of transformer (costs alot to ship) for a 1.25KW system I designed with no transformer. It can be done, there are drawbacks and adavantages.
I think the latest comments about uploading files that are available elsewhere on the web are a little late when it comes to this posting. Did any of you bother to look at the date of the orignal post? Comments/questions/answers to postings that are over 3 years old probably won't get much attention from the original poster.