# Trouble wrapping my head around it.

Discussion in 'General Electronics Discussion' started by dave.martin, Sep 13, 2012.

1. ### dave.martin

26
0
Sep 11, 2012
So I have receitly jumped into test and trouble shooting my broken electronics around the house. I have a good understanding of DC voltage since I am an automotive mechanic and well besides an alternator it's all DC Viltage. So my question is when testing a bridge rectifier on a live board where is my ground on the circuit? I would assume its the - pin off the rectifier but I am not that sure of myself on this.

2. ### CocaCola

3,635
5
Apr 7, 2012
AC in DC out just like this... The ground will be the negative out of the bridge rectifier...

3. ### dave.martin

26
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Sep 11, 2012

ok so this is what I am working with and when I turn the TV on and have my test leads on pin 1 and 4 (red to + and black -) and fluke set to test DC Voltage..
I get 341.9 V DC does that sound correct? It seams higher than I thought it should be. I have beeen talking back and forth with (*steve*) in the repair section of the forums and he said that it should be around 170V DC.

4. ### (*steve*)¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥdModerator

25,500
2,840
Jan 21, 2010
No, the capacitors are in series, and quite likely there is some voltage doubling occurring.

As I said in that other thread (*why* did you start another one?) I would expect about 170 or 340 volts.

You say you have the capacitors in series, and each one has about 170V across them, adding up to 340 volts.

Of course it is possible (but unlikely) that you have 340V across each, but since you are telling me your mains voltage is 120V, even if the device had a 110/220V switch, placing it in the wrong position would reduce the voltage, not increase it.

5. ### dave.martin

26
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Sep 11, 2012
i apologize for another thread I was trying to figure out how the rectifier worked and why I would be getting the voltage I was... I was having trouble finding information as to the outout of them that was what I was after in this forum here I was not trying to start multipules of the same thing...