An fun lab project would be to use a long coil, cover it with solar cells to power the coil, a polarity reversing switching circuit, LED, a photo sensor tuned to the frequency of the LED, a small mirror, and a very low friction bearing.
Imagine the coil as the pointer of a magnetic compass.
Mount the LED along some point along the length of the coil so that it will pass over the mirror at the point in coil rotation at the magnetic equilibrium position (North, South, North South) where the light of the led will be reflected onto the photo sensor triggering the polarity reversing switch. Balance Mount the package on the low friction bearing. Expose it to strong sunlight, align the package North, North, South, South relative to the geo-field and let it go. As it begins to turn to align North,South, North, South, the energy from the solar cells will be converted to the rotational energy of the coil turning. As the coil moves towards the magnetic equilibrium position the rotational energy will carry it through the point of magnetic equilibrium polarity at which time the led passes over the mirror, reflected into the photo sensor, activating the polarity reversing switch, and further accelerating the process. Hopefully it will go round and round and round, faster and faster until the power from the solar cells are equal to the power loss due to the dynamic drag of the system.
The Questions?
At what relative field angle would the power flowing in the circuit be greatest? At what relative field angle would it be at a minimum?
Could the power be calculated as a function of coil acceleration and bearing and aerodynamic drag?
Could the bearing drag be derived as a function of coil acceleration, circuit power, and aerodynamic drag?
How?
Gavilan
At what relative field angle is the power at max?
Re: At what relative field angle is the power at max?
