Transformerless Power Suppply

[dhouston]

I have mentioned before that some of Microchips Application Notes are downright dangerous... and that is one of them.

Connecting Neutral and Earth together will trip most ELCB's a small fact that the author of that AN seems to have overlooked. Not fusing the Live is plain stupidity (as is any power distribution system that allows users to plug appliances in either way around)!

Melanie,

This may be accurate when talking about UK or European wiring but your advice is both inaccurate and dangerous when it comes to North American wiring. The fuse between neutral and ground shown in FIGURE 3 and FIGURE 4 of TB008 is a safety feature as the authors of the app note state.

Here's a URL which briefly explains the 3-wire system used here for many, many years.

• http://hyperphysics.phy-astr.gsu.edu...ic/bregnd.html

Circuits which might be plugged in either way around will not have the ground wire and thus will not have the fuse and will also require double-insulated, non-conductive enclosures. In fact, the only way to plug a North American two-wire appliance in either way around is to file down the wider neutral prong of the polarised plug.

You might also read...

• http://en.wikipedia.org/wiki/Double_insulated