The Tritium circuit was the first (to my knowledge) type 3 SE. As such, it is quite experimental, and should be regarded as a prototype rather than the ‘state of the art’! Nevertheless, it does function reasonably well, and in some circumstances outperforms other solar engines such as the Freds that I have lying around. [...]
How do we achive 10nA operation? By using diodes in place of pull up resistors, and by isolating the DC load from the trigger circuit via junction drops and the 10nF capacitor. If there is too much power comming from the solar cell then the motor might run too often or even continuously. You can [...]
This circuit is used to measure the current from a solar panel. It has very low power loss for currents in the 0-10A range. It also works as a general purpose DC current meter. The circuit can be used on either the positive or negative side of a DC circuit. Read more original source: http://www.solorb.com/elect/solarcirc/imeter/index.html
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