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| [SOLVED] Advice need to build a capacitive power suply |
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| Chriss:
Hi! I'm searching for a way how to build a simple but safe capacitive power supply for my diy projects. I saw several type of them in many devices like a day light switch device etc. what is powered from main 220v power supply and controls a relay etc. So, my goal should be: 1. should be safe 2. simple as much as can 3. max current what it should deliver is something around maybe 100mA or a bit higher. I wish to power 5/12vdc relay, microcontroller... ( is it possible to handle a current maybe around 400-500mA? would be better) I saw several options with a cap in series of the live and neutral line, but after reading on the net I found does sometime it is dangerous even they have cap's on the neutral and live line too. I'm focusing on informations from thisl link: https://www.electroschematics.com/5678/capacitor-power-supply/ Would that schematic on that web site above do the job? So, what can you advise me? what you think would be a most simple way to make a balanced capacitive power supply? Safety must be on first place because the main power supply... Thank you for any schematic or help. My best regards. |
| glarsson:
Don't do it. It is not safe to use as a PSU you can touch. Even the article you linked to put in warnings at the end (should have been at the beginning of the article). |
| MarkF:
--- Quote from: Chriss on January 29, 2019, 08:13:22 pm ---I'm focusing on informations from thisl link: https://www.electroschematics.com/5678/capacitor-power-supply/ Would that schematic on that web site above do the job? --- End quote --- Why? My advise is "Don't do it". Just build the typical linear power supply. The transformer gives you isolation from the "mains". Then buy a proper lab power supply when you can afford one. |
| Chriss:
Sorry, maybe I didn't explained well what I wish to do. I don't wanna make a bench power supply, I have several in my lab. I wish to make a "universal" power supply for my project when I finish them on my bench. Let's say if I make a day light sensing circuit to activate a relay when night is falling, I would avoid the usually way to power on my device with a 12v power adapter and then feed the line voltage into the device etc.. too much cables, hard to fit in into the box etc. So, I won't use this type of psu on my bench, but on my final product. On my bench I have also an isolation transformer from the main too for safety purpose... I'm just curious to power my final product with such of capacitive psu... |
| soldar:
The only reason to build this is to power something which uses very low power and wich is totally and completely and safely enclosed and cannot be touched at all. Many small devices are powered like this, timers, etc. If it is for a very specific project which you close and seal and is safe then it might make sense. If you are going to be messing with it then you are better off providing an isolation transformer. Look at my thread where I was trying to repair a volt/amp panel meter and the problem turned out to be precisely the power supply capacitor. All my testing was done using an isolation transformer. https://www.eevblog.com/forum/repair/repairing-panel-volt-amp-meter/ |
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