The Evolution of the Solar Engine

This page is my humble attempt to try and capture the design and evolution of the BEAM SE. The idea is to try to capture the incremental changes and mutations from one design to another. This is somewhat similar to the taxonomy used for biological species. (In this case Intelligent Design may be more appropriate but don't get me started on that...). Let me stress again that this not the way these circuits were designed.

It is not a record of the history of these SEs but rather an exploration for further development of these circuits by using a generalized approach (to paraphrase Wilf here)

This taxonomic system uses the circuit "mutations" and changes as a guide. It does not describe the chronological order in which these SEs were created.

One of the things that can be learned from this system is how to combine ideas, get inspiration for new designs, and perhaps find "missing link" designs.

I tried to build a hierarchical structure starting from the root design of the Solar Pock-Mark.
The Pock-Mark is perhaps the simplest circuit that contains all the elements of an SE, the power source (solar cell), the storage unit (e.g. capacitor) and the load (e.g. LED, motor), it does not have a latch mechanism. All sibling designs, have the same colors. Evolved designs are contained in nested boxes.

There are many other variations that I missed, don't know or simply didn't know where to put. I welcome suggestions and comments.

Most of the graphics and circuits on this page were done by others, more talented than I. All the credit goes to them. I have tried to link to all the sources (click the image to go to the source). I'm sure there are errors and mistakes, they are most probably mine and not others'. If you see an error and/or problem please let me know. If I'm using one of your designs against your wish, please let me know and I'll remove it.


Proto-BEAM: The Solar Pock Marks

Possibly the simplest BEAM circuits.
The Pock-Marks contain all the elements of an SE, the power source (solar cell), the storage unit (capacitor) and the load (F/LED).

However, what makes it a Proto-BEAM circuit is that it does not have a latch mechanism.



The Divine Intervention SE

This is perhaps the simplest and most primitive in the evolutionary sense of the BEAM SEs. It requires an external trigger (divine intervention) to run the motor.

Specifically this design has a problem that the accumulating cap. voltage might ruin the solar cell.

This design has a diode in series with the negative rail avoiding possible damage to the solar cell.

This design also incorporates a transistor latch.

The latch introduced in this design is like the one used in the FRED design.

SCR Based SEs
This SE may, in fact, be a version of the common evolutionary ancestor of many the other SEs, specifically these using an one PNP and one NPN transistor. This is due to the nature of the SCR.




The SCR solar engine was designed by John Iovine of Images SI Inc.
The circuit was first published in Nuts & Volts Magazine, June 1996

Diode Based SEs

The Simple FLED SE

In low light, it's a Type 1 SE (Voltage controlled), and in bright light,
it's a Type 2 SE (Time controlled). The reason is, there is no transistor
latch for the SE. It's only on when the FLED is on. Another cool feature is, when in bright light, there is a maximum ON time.

The Zener-based SE

The two diode SE

FLED-based SEs


The LED Logic SE

1381 Based SEs

Standard 1381 SE

1381 Based SE with light sensitivity

The Miller 1381 SE

The Miller 13812 SE

Similar as above but uses the 13812 and a PNP transistor.

[Move mouse over the circuit to see the differences from the Miller 1391 SE.]

.:: © 2004 Adi Shavit ::.