Understanding the Sunking layout...

[Gledison]

Hey guys, i was finishing my silkscreen for the Sunking build and i started to look more into details to the tracks, components;why they are connected in such a way, etc... im still in the beginning of my learning curve (well, still a line ) and a lot of things are still not clear...
Im having a little trouble to understand the connection between C20 and C21. I thought that electrolytics caps should have the negative lead grounded. The negative lead of C20 is connected to the positive lead of C21. I understand that the electrons are flowing from the positive to the negative (ground) points. what i dont understand is that this 2 points are directly connected :S
Any help to understand it?
thanks guys

[m-Kresol]

They don't NEED to go to ground as far as I know. Connecting the negative lead of electro 1 to the positive lead of the second one makes sense, since the +9V is applied at the pos. lead of electro 1, goes out of its negative lead so to speak and then passes to the second electro through the positive lead again. The voltage will drop of course over the first capacitor, but will still be >0V. Therefore, it has to be connected to the anode again. Hope that makes sense.

[mattlee0037]

 They would be wired 'in series' in the way you described sometimes used to make parts sourcing easier as you can create your own values.

[RobA]

Look at the spec sheet for the LT1054 charge pump. It has about the best description of the way these types of parts work. It also has various example circuits. The charge pump section of this layout is a combination of two of the standard circuits, the voltage doubler and the voltage inverter. If you look at those two, you can piece together what is going on. Pin 2 is always more positive than pin 4, so the cap that goes between them for the inverter circuit makes sense in its orientation. If you then look at the positive voltage doubler circuit, the negative side of the cap hooks to the + pin (pin 2) and the positive side of the cap hooks to the point between the two diodes that sits near 18V. So, even though the two caps come together at that point, they are only hooked to each other because they come together at that point, but serve two different purposes. The orientation of them both makes sense because they both have the more positive voltage on the + side of the cap.

[Gledison]

Look at the spec sheet for the LT1054 charge pump. It has about the best description of the way these types of parts work. It also has various example circuits. The charge pump section of this layout is a combination of two of the standard circuits, the voltage doubler and the voltage inverter. If you look at those two, you can piece together what is going on. Pin 2 is always more positive than pin 4, so the cap that goes between them for the inverter circuit makes sense in its orientation. If you then look at the positive voltage doubler circuit, the negative side of the cap hooks to the + pin (pin 2) and the positive side of the cap hooks to the point between the two diodes that sits near 18V. So, even though the two caps come together at that point, they are only hooked to each other because they come together at that point, but serve two different purposes. The orientation of them both makes sense because they both have the more positive voltage on the + side of the cap.

That's a nice explanation, it helps to understand this orientations..
thanks a lot