80hinhiding
Well-known member
- Joined
- Sep 27, 2016
- Messages
- 97
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It's as hard to answer generally as a question like, "What is the best wine to pair with chicken?" You just need to follow JR's advice, and try to minimize ground impedance. You really need to include the rectification into the picture as well.80hinhiding said:In the attached graphic I just made, which layout/wiring is the best to use in a power supply? And why?
The way the caps are connected together is not as important as the way they are connected to the rest of the circuit; you have to understand that "ground" has a resistance that allows rectifying currents to develop parasitic voltages and that these parasitic voltages should not be allowed to mix with the signal flow. See attached. As JR mentioned, keep all connections short and solid.80hinhiding said:In the attached graphic I just made, which layout/wiring is the best to use in a power supply? And why?
Adam
abbey road d enfer said:The way the caps are connected together is not as important as the way they are connected to the rest of the circuit; you have to understand that "ground" has a resistance that allows rectifying currents to develop parasitic voltages and that these parasitic voltages should not be allowed to mix with the signal flow. See attached. As JR mentioned, keep all connections short and solid.
NO, use as much capacitance as you need/want to keep ripple voltage within desirable range.80hinhiding said:I hate to admit it but I'm still confused. Are you saying not to use too much capacitance directly after the diode full wave bridge
It is not about distance per se, while resistance of PCB traces or wires increases linearly with length.rectifier, and to keep the junctions a specific physical distance from things like the regulator?
The crap needs to go down the sewer, the confusing thing about "ground" is that it must both be dirty and clean (I know that isn't helping).The concept of keeping the crap out of the ground is not really clear. I understand we're filtering out frequencies and creating a DC waveform for the sensitive audio circuits, and we don't want other junk showing up there.
The current flow when charging reservoir caps is mainly at the peak voltage of the mains waveform. This current will develop a voltage across even short traces/wires and this voltage is the all too familiar hum/buzz we hear from poorly designed products. This current is unavoidable, and larger caps will generate higher peak current, but smaller ripple voltage so a common tradeoff.I've noted to keep my connections short and layout tight, to minimize resistance.
Edit: I'm reading this document right now: http://www.valvewizard.co.uk/Grounding.pdf
A
It doesn't matter as much where the one ground point is, only that there is only one point.80hinhiding said:This is quite interesting. Hmm
So would two tinned bus wires, a smaller circle inside a bigger circle be of any benefit? The smaller circle for ground reference, one point only in the center of them all. Positive lead of cap to the bigger circle bus, negative lead to the inner circle bus.
it was meant literally (while the sewage allusion is figurative).Is that taking the idea too literally?
probably not... you are confusing magnetic or electrostatic interference that travels through the air... Layout is all about conducted interference through electrical connections.Should I shield the reservoir bank from the rest of the power supply with some copper?
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