Strange voltage drop on CRC filter.

Papabravo

Joined Feb 24, 2006
12,890
Why do I get an advertisment that I can skip and what is up with needing Flash Player. If you want people to help you with your problem you absolutely have to stop throwing up obstacles to us doing that. Just include the image in your post. Is that explicit enough for you or do I need to use a 2x4 to get your attention?
 
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Lestraveled

Joined May 19, 2014
1,946
You should be getting 336 volts across your output points. Your ground is meaningless and is basically floating.

Your second photo link works for me.
 

Veracohr

Joined Jan 3, 2011
695
I can see it just fine Papabravo, and I don't have Flash.

Coinmaster, do you mean you're seeing +170V and -170V (340V between the two), or only 170V across the two?
 

Thread Starter

coinmaster

Joined Dec 24, 2015
502
I can see it just fine Papabravo, and I don't have Flash.

Coinmaster, do you mean you're seeing +170V and -170V (340V between the two), or only 170V across the two?
170v across the two. The voltage taken directly from the rectifier output is +/-170v. and exits the filter as +/- 170v.
 

AnalogKid

Joined Aug 1, 2013
8,302
I should be getting like +/- 300v after the rectifier but I'm only getting around 170v.
I've confirmed the AC before the rectifier is 240v.
Since there is a GND symbol on your schematic, your statement about +/-300 V is incorrect. You will get approx +/-170 V. 240 x sqrt2 = 340. With a centerpoint voltage divider, that's +/-170.

However, capacitors make horrible voltage dividers, primarily because large electrolytics can have tolerance specs of -20%/+80% or worse. So while the outside terminals probably will measure 340 V, the centerpoint will wander around with temperature, load, the phase of the moon, etc.

ak
 

Thread Starter

coinmaster

Joined Dec 24, 2015
502
Ah, so in order to get +/-340v I would need double the AC voltage, I'm guessing the waveform is split in half giving half the rms voltage of the AC, I have much to learn it seems.
 

Lestraveled

Joined May 19, 2014
1,946
Ah, so in order to get +/-340v I would need double the AC voltage, I'm guessing the waveform is split in half giving half the rms voltage of the AC, I have much to learn it seems.
Yes. Connect one of your AC inputs to your ground and you will get +336V and -336V around ground.
 
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