Transformerless Power Suppply

[sayzer]

...

I have designed and made a fridge controller (Blind type) with 555 and
similiar transformerless power supply some 3-4 years ago. I have used
normal 680n / 250V capacitor --( our system is 240V 50Hz) and those are
working nicely last 3-4 years and saving 100s of Rs. every month for the
users without any recall.

Now it would be a good time to post that schematic here.

BTW; let me remind you that Melanie has a Klingon cloaking device.


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[Melanie]

Take a hundred engineers and give them the same problem, and you're likely to get a hundred different solutions, and each will argue that thiers is the best approach. I think this thread has been pretty much done to death, and there's more than enough information here for anyone but the most inept to design their own. And they, through natural selection when playing directly with the supply mains, will ensure that the standards remain high for the rest of us on the forum.

[dhouston]

Now it would be a good time to post that schematic here.

Just do a web search for X-10 schematics. They've been using a metallised film cap and series resistor for many years in the millions of UL approved switches and modules they've sold.

• http://www.edcheung.com/automa/ws467.gif
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[Luciano]

Hi,

About the resistors:

(Click to enlarge the picture).

Best regards,

Luciano

[psdayama]

Now it would be a good time to post that schematic here.

BTW; let me remind you that Melanie has a Klingon cloaking device.


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Hi sayzer,
well here is the schematic. Im not so good in drawing like U.
I had a fridge which had thermostat gone bust. So I made this ckt and
saved lot of energy 0.75KWHr /day instead of 5KWHr/day. I also found
that most of fridges have improper settings evenif the thermostat is OK and
there is lot of frost and they consume abt 3-4 KWHr/day. So making a
commercial unit costing Rs.400/- ( $9 appx.) have installed in abt 20-30
homes and they are all saving energy down to 1KWHr/day.
The consumption of unit is less than 05VA and there is no area even feeling
warm. I cant afford to use X2 capacitors in this as that will push cost of unit.

[Pic2008]

Can someone explain to me how the 240VAC after rectification can come down to +12VDC?

[financecatalyst]

Can someone explain to me how the 240VAC after rectification can come down to +12VDC?

Are you kidding me? I have enjoyed the arguments a lot, and from the first post to the third last (subtracting yours & mine of course), I have come across 2 to 4 circuits all making 12VDC. Check them out going back few posts (Remember to use X2 capacitors with mains - else Melanie would not like it - in case she comes across your circuit )