"Smoking Gun" - finally!

[PaulLowrance]

@Paul

Just one question... one the array attached to the Mylar cap you obviously dont have any extra caps or resistors. But on the board version you have SMD resistors and caps.....are those needed?

Is their any critical spacing requirement if one was to place the diodes on a PCB? How close can you place them?

In the first image in photo page -->
http://greenselfreliantenergy.com/experiments/photos/
you'll see three types of diode arrays. The large one, right side, is Tom Schum's. To left of Tom's, very top, is my first diode array. I made it while waiting for the PCB's to arrive. The solder traces were made with room temp liquid solder pen. The R's and C's were bought at a local store. This diode array forms what I call a JNR2d circuit. Don't use the JNR2d circuit!!!  It's unnecessary. The JNR2d circuit was designed because every Spice simulator *incorrectly* simulated diode noise. It turns out diodes actually produce Johnson noise equivalent to their dynamic resistance. I forward the proof of this to Mike, the creator of LTspice, he confirmed it, and LTspice now has the correct diode noise math equations. Although, back then we didn't know about this error in Spice, so we used an external resistor to produce the Johnson noise, and the caps were used to block the DC current.  All of those R's and C's are unnecessary. You only need diodes. In that same photo, left side, the middle diode array, is the same JNR2d circuits except it's on a PCB, and the R's and C's are small, 402 SMD.

In the same photo, left side, bottom diode array, you'll see a wall of diodes connected to a Mylar cap. That is the diode array people should make. The second photo shows a close up image of this diode array. It is wall of SMS7630 diodes, 156 of them in-series.

PL

[PaulLowrance]

I just created an animation of how the diode array chip would be fabricated in a vacuum and using deposition -->

http://greenselfreliantenergy.com/forum/index.php?topic=18.msg90#msg90

PL

[sm0ky2]

One question ...

If one diode fails will not the whole array not work leaving us with a set of old school xmas lights that don't work cause there is one bad apple.

We got to think of these things even in beta stages.

-infringer-

one solution to this problem will be a secondary parallel (resistive) connection on each module in the array
should 1 diode fail in any given module, it will take the parallel route through the resistor basically skip over the bad module,  you have a slight loss, but you wont lose the entire array.

important is to make sure the resistor value is GREATER than the total resistance of the module.
so the primary path will be through the series connection.

[PaulLowrance]

A parallel array by itself does not solve the problem. Paralleling has big problems with shorts. A single short would render a parallel diode array useless.

The solution would be a combo of series and parallel. Although for the moment I cannot recommend placing diodes in *direct* parallel to each other because it decreases the kTC noise. Therefore, there's no reason why not to place at least a dozen diodes in-series first, and then in parallel. That way, no two diodes are directly connected in parallel.

PL

[sm0ky2]

A parallel array by itself does not solve the problem. Paralleling has big problems with shorts. A single short would render a parallel diode array useless.

The solution would be a combo of series and parallel. Although for the moment I cannot recommend placing diodes in *direct* parallel to each other because it decreases the kTC noise. Therefore, there's no reason why not to place at least a dozen diodes in-series first, and then in parallel. That way, no two diodes are directly connected in parallel.

PL

maybe i didnt describe what i was talking about well enough.

what im saying is to add a parallel "shortcut" around EACH module in the array (or group of series connected diodes) so if 1 diode becomes "open" somehow or fails to conduct electricity (wasn't layered perfectly inside the chip, whatever other failure we cant think of)
the flow of current will not be disrupted, it will simply flow through the resistive circuit to the next module or group of diodes.
and the entire array wll continue to function as normal (minus the failed group/module).
the resistor in the shortcut path should be slightly higher han the resistance of the combined diodes it is going around, so it will not affect the functionality of the device except for the loss of the failed module.