Hand-cranked generator 's Palace training materials science gizmos Technology DIY small production

Fun hand-cranked generator small production, this product is DIY kit, making simple, fun is very high. Accordance with the instructions, right after production, this map can be obtained hand-cranked generator, in the dark, gently turn the handle, you can turn on the LED lamp. [] Body size: 4 * 4 * 5.5 cm Crank [System]: 5.5 cm [Weight]: 54 g The generated voltage []: High-speed, uniform rotation can reach 3V, the LED lights that came