Are there electric generators that can generate electricity when spun?
Are there electric generators that can generate electricity when spun clockwise and then in reverse? For example, a generator that can be used for sinusoidal and periodic motion instead of continuously turning the same way. Any simple generator will generate electricity when spun in either direction. However the output voltage and frequency varies with the rate of spin, and so youll probably want to convert the output before using it. One way would be to use it via rectification to charge a battery, and then if you need AC output use an inverter to convert from the steady battery DC to AC with stable voltage and frequency. Note that the angular momentum of the generator will affect whatever periodic device youre using to turn it, effectively adding mass, and the generator torque (most of which is whats creating the electricity) will work to reduce the magnitude of the periodic motion. In fact I have a watch somewhere that does something similar to this on a very small scale, except for the inverter bit. It uses normal motion of the arm of the person wearing it to move a pendulum which turns a tiny alternator. The rectified output is dumped into a capacitor in this case, and the electronics inside the watch are designed to work with the gradually changing DC voltage across the capacitor. There are other similar devices around that use the same principle.