How would you add pi filters to a bipolar power supply? A or B? Picture attached

[Metatronic_Mods]

I think my confusion here stems from the fact that I still have a hard time visualizing current flow in bipolar powered circuits. But, which would be the proper layout, or is it something else? Picture attached.

[Jay_Diddy_B]

My vote goes to A.

The reason: you want to keep the ground continuous.

If you use 'B' and the source and device have a ground connection, the inductor in the ground lead gets shorted.

Jay_Diddy_B

[timb]

Think about it like this: If you were to use that -12V rail as GND at your device, then what you have labeled as GND would be +12V and what you have labeled as +12V would actually be +24V.

Essentially, voltage is the potential difference between two points. So, the difference between -12 and +12 is 24, right? Make sense?

[timb]

My vote goes to A.

The reason: you want to keep the ground continuous.

If you use 'B' and the source and device have a ground connection, the inductor in the ground lead gets shorted.

Jay_Diddy_B

No, they're polarized caps. If you use A, the caps on the -12V rail would be backwards and eventually break.

Remember, 0V is more positive than -12V. You want the + end of the polarized cap towards the more positive end.

Edit: Actually, looking at his schematic again, neither A or B is correct. It should be A with the -12V caps flipped.

This would actually be correct:

[Metatronic_Mods]

My vote goes to A.

The reason: you want to keep the ground continuous.

If you use 'B' and the source and device have a ground connection, the inductor in the ground lead gets shorted.

Jay_Diddy_B

No, they're polarized caps. If you use A, the caps on the -12V rail would be backwards and eventually break.

Remember, 0V is more positive than -12V. You want the + end of the polarized cap towards the more positive end.

Edit: Actually, looking at his schematic again, neither A or B is correct. It should be A with the -12V caps flipped.

This would actually be correct:

I didn't mean to imply polarized caps, that's just the default symbol I use. Polarized are indicated with a +

[Metatronic_Mods]

Always do B, with corrected capacitor polarity. Don't break GND unless you know what're you doing.
BTW, pi filters are supposed to be used with capacitors or inductors with some ESR, don't get super ideal parts. There will be ringing when input or output has a voltage/current impulse.

You say don't break GND, but B has GND broken by one of the inductors. I'm confused.

[Metatronic_Mods]

Think about it like this: If you were to use that -12V rail as GND at your device, then what you have labeled as GND would be +12V and what you have labeled as +12V would actually be +24V.

Essentially, voltage is the potential difference between two points. So, the difference between -12 and +12 is 24, right? Make sense?

Yeah, that's how I tend to think about it. I think the reason I get confused is that the systems I work on are never balanced well (more current in the + rail than in the - rail), so there's always a return current in the GND (or what you might label +12V) going back to the power supply.

[timb]

My vote goes to A.

The reason: you want to keep the ground continuous.

If you use 'B' and the source and device have a ground connection, the inductor in the ground lead gets shorted.

Jay_Diddy_B

No, they're polarized caps. If you use A, the caps on the -12V rail would be backwards and eventually break.

Remember, 0V is more positive than -12V. You want the + end of the polarized cap towards the more positive end.

Edit: Actually, looking at his schematic again, neither A or B is correct. It should be A with the -12V caps flipped.

This would actually be correct:

I didn't mean to imply polarized caps, that's just the default symbol I use. Polarized are indicated with a +

Okay, then A would be correct. As for your symbols, the use of a straight line over a curved line to represent a non-polar cap isn't really common anymore (I've only ever seen it in old American schematics). You might want to switch to using two straight lines, which is the current international standard, so your intent is communicated clearly. After all, that's a big part of engineering.