Society of Robots - Robot Forum
Electronics => Electronics => Topic started by: TheElabaman on January 02, 2007, 03:46:52 PM
-
I am new to electronics, for the most part. On this solar engine schematic, I don't understand exactly how it works. I realize that the transistors + Flashing L.E.D. + resistor create a voltage trigger. But I don't understand how. Could anyone provide a step by step list of what the current is doing at particular times?
Also, after the capacitors are full [3 X 1000uF in parallel], do they not impede the current?
Thanks.
-
1: As the solar cell receives light, it generates electrical energy, which is absorbed by the 3000uF capacitor.
2: Once the capacitor is charged with enough voltage that the FLED can be triggered, it does so, thus also providing the necessary base current for the 2N3906 to activate.
3: the collector of the 2N3906 sends an amplified current to the 2N3904 which in turn amplifies again the current and draws a large amount through the motor, causing it to spin.
4:The voltage on the capacitor begins to drop because of the large current consumption of the motor which the solar cell is not capable of constantly maintaining.
5:The voltage goes below the minimum needed to keep the current flowing through the transistors, de-activating the circuit until the solar cell again charges the capacitor to the sufficient voltage to activate the FLED, restarting the whole process.
note: since the 3000uF cap is connected in parallel with the rest of the circuit it does not impede the current flow to it. it's purpose is to store the energy from the solar cell over a length of time and then release it in a quick burst.
-
the resistor exists to allow you to adjust the trigger voltage. low resistance creates lots of quick weak pulses, large resistance creates a few big pulses.