SMPS - Switching Mode Power Supplies - Any example ?

[mister_e]

eeuuuhh 0.05 mA or 0.05 A

[flotulopex]

... had a translation problem.

It is 0,05A or 50mA.

[mister_e]

same thing to me, but it make much sense...

for ONLY 50mA, i don't think it really worth to build something really complicated and over price the whole thing. Maybe the Melanie's Transformerless Power Supply example could be enough with few mods.

My english is really bad.... :-)

mine too, but... who cares

EDIT: maybe something around those one
http://www.discovercircuits.com/DJ-C.../offline5v.htm
http://www.st.com/stonline/products/...re/an/8313.pdf

be really careful with that kind of stuff..

[keithdoxey]

EEEEKKKK!!!!!!

OK, so it does say that the circuit is NON ISOLATED and DANGEROUS VOLTAGES EXIST EVERYWHERE but I would suggest that by having the dropper resistor in the neutral leg rather than the HOT leg, it is making it more dangerous than it need be.

If the resistor fails then the circuit stops working but EVERYTHING WILL STILL BE LIVE whereas if the resistor was in the live leg and failed then it would still stop working but the majority of the circuit would only be connected to neutral. Still wouldnt want to touch any part of it though!

Obviously using a 2 pin mains connector would mean that there is no guarantee of polarity anyway so the above point would be irrelevant.

[mister_e]

i agree, it's ALWAYS dangerous if not properly insulated from the user.

You could be surprise to look at some TV schematic... no coincidence why the user button are as this far of the front plate and have those plastic shaft in between.

If you know what you do, if you install enough protection, if you screen the user from any potential risk, life is good.

You don't want to reverse engineer most programmable thermostat, cofee maker, etc etc...

Advanced components industries, do some nice small transformer.
http://www.advancedcomponents.com/go...FQy8QAodBl8-OA