| ??? 03/27/12 23:03 Modified: 03/27/12 23:06 Read: times Msg Score: +1 +1 Good Answer/Helpful |
#186923 - Capacitor power supplies... Responding to: ???'s previous message |
Chico said:
I know about all danger in this, I dont need an alert. Then why the bloody hell are you toying arround with it??? Chico, this isn't a game but real life! You were not the first man being hurted or even killed by mains voltage, believe me... Here is a link explaining capacitor power supplies in more detail: http://ww1.microchip.com/downloads...00954A.pdf Read it carefully, especially the chapter "safety considerations". What is shown there is not a "nice option" but in most countries a MUST. So, you NEED a fuse, you NEED R1 and you NEED R2. Also, R1 and R2 MUST be surge proof, i.d. they must be able to withstand surge voltages of several thousands of volts. Also, C1 MUST be an X-cap! D1 MUST also withstand inrush and surge currents, so, you would not use a simple zener diode but a ROBUST TRANSZORB or TRANSIL, which quits an overload by a short circuit and not open circuit!! VR1 is critical. Varistors were widely used in the passed. But overloads often resulted in an increase of leakage current and one fine day the varistor became so hot that it started to burn. Many fires occured because of an overheating varistor. Also, during surges a varistor tends to explode. So, today, when using a varistor, it NEED to be mounted with a temperature fuse and the ambient NEEDs to be protected against eventual explosion. Kai Klaas |
