Bridge Rectifier Problem when connected to Wall Power Outlet

EDAboard.com Forum Index -> Power Electronics -> Bridge Rectifier Problem when connected to Wall Power Outlet

Author

Message

richeek

Joined: 05 Feb 2008
Posts: 3
Location: College Station Texas

06 Nov 2009 5:56 Bridge Rectifier Problem when connected to Wall Power Outlet

Hi all
I know this is a long post but I tried to put everthing...

I am making a bridge rectifier to give DC voltage to another circuit. At the output of the rectifier I am connecting 0.47uF-250V, mylar capacitor and across the capacitor I am connecting resistive load.
The bridge should rectify 120 VAC from a WALL OUTLET to obtain a DC voltage. I am trying to acheive as close as possible to 170 VDC.
Now the problem is that I want to get this voltage with respect to circuit ground. What happens is if I try to connect other end of the capacitor to ground some diodes blow off. Even if I try to connect oscilloscope between two terminal of capacitor some diode blows off.
I searched it over the net and found out similar post: http://www.electro-tech-online.com/e...r-problem.html
I think I am also facing the similar problem. Could anyone please tell me why this is happening? Why the other end of the capacitor is not always at potential 0V? What should I do now to get a 170V DC power supply?
I mesure the voltages at both ends of the capcaitor by just connecting positive terminal of a 10X probe to the circuit and floating the probe's ground. And I saw that capactor terminal that I think should be at 0V is actually oscillating between 0V and -170V.
At the same time other end of the capacitor is oscillating between 170V and 0V. Hence together they will give me 170VDC. But how to connect them to another circuit?
Kindly provide some inputs I am so confused.
Thank you.
Sincerely
Richeek Arya