EEVblog Electronics Community Forum
Electronics => Beginners => Topic started by: peter123 on October 27, 2014, 10:37:12 pm
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Greetings,
I'm building a system with high voltage supplied from a voltage doubler, and a lower voltage DC supply. The plan is to use a transformer and a rectifier bridge to provide the low voltage DC (see attached schematic). The circuit will be connected to mains power.
The output of the voltage doubler and of the rectifier bridge needs a common ground point, because the high voltage will be controlled by the lower voltage using a transistor. Is it okay to hook up the negative terminal of the voltage doubler to that of the rectifier output? I'm scared it will create some kind of ground loop since the potential difference is really high if the nets aren't connected.
Regards,
Peter
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Well,it would work,----- BUT!!
If it is designed to be hard wired to the Mains Supply, enclosed in a double insulated enclosure,& dedicated to supply power to some device with no wired connections to the rest of the world,other than the incoming Mains,it would be OK.----,of course,all dependent on the approval of the Regulating Authority.
Somehow,though,as it is in the "Beginners" section,I doubt if that is the case. ;D
As a bench power supply,it has several problems:-
(1) Mains Active & Neutral can be transposed at power sockets.
If they are,Active is connected to your "common ground" on each negative half cycle of the Mains,making it "hot" with respect to Mains Earth------you can get "'zapped" :o
(2) If the situation in (1) exists,& another device with its "common" connected to Mains Earth is connected
to your power supply,the bottom diode of your doubler shorts the Mains supply on negative half cycles ----Goodbye diode!!!
(3) If you manage to get your Mains connections correct,& connect another device as in (2),you will short out the bottom capacitor of your voltage doubler---"zap"
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Thanks for your reply! :) Do you have any suggestions on how to build a circuit like this in a more proper manner? I'm trying to build a capacitor charger circuit, where the caps of the voltage doubler are charged. Hence the current through the voltage doubler will be quite high (I'm using a current limiting resistor).