MicroPower Solar Engine


Posted on Feb 6, 2014    9185

If you have a power source which will provide 2. 5Vdc at 10uA this circuit should drive a pager motor. It turns on the motor at 2. 3 to 2. 5Vdc and switches off at 1. 2 to 1. 5Vdc. Both Steve and I have built ( bread boarded or haywired) the business end of the design and achieved similar results. This does not mean that it will work for everyone but it should. [I used a BC559C (Q1), a BC549C


MicroPower Solar Engine
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(Q2) a BC559B (Q3) and a BC337-25 (Q4), which happened to be in the bitbox. SB] Enable power to the circuit. If the circuit works properly, the voltage will rise to a firing point, turn on the motor momentarily which discharges the capacitor to level where motor has little current passing through it but Q1 and Q2 are still conducting. At this point, . In practice, I removed R1, measured its value and replaced it with a standard resistor value 5 to 10% less. 560K was the value that both Steve and I used which shows just how repeatable this design is or how lucky we were. Note: It is realized that this presentation is very cryptic. If it were delayed until a complete circuit description and circuit layout were complete, it may not have been presented at all. It is hard for many to realize the time and effort it takes to create the circuit cards, obtain the correct parts, make up the kits and write assembly / debug instructions. The dollar cost and other risks are not minimal. The first results from building a number of units. It was found that R1 could be replaced with a 680K resistor rather than using a pot. R6 was added to limit the current used to drive the base of Q4 which meant that more current became available for the motor. 390 Ohms is the smallest value that should be used for R6, it can be larger depending upon the motor and drive transistor (Q4) combination. There is one further proposed change that could improve...




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