Abstract: A rotatable device powered by continued electricity supply, having a supporting shaft, a bearing, a rotary body, a mounting seat, an electrical conductive member, and a brush. The bearing includes an outer ring and an inner ring. The rotary body is connected to the outer ring. One of the electrical conductive member and the brush is connected to the rotary body, and another one of the electrical conductive member and the brush is connected to the mounting seat. A windmill that uses the rotatable device is also provided.

Abstract: A rotatable device powered by continued electricity supply, having a supporting shaft, a bearing, a rotary body, a mounting seat, an electrical conductive member, and a brush. The bearing includes an outer ring and an inner ring. The rotary body is connected to the outer ring. One of the electrical conductive member and the brush is connected to the rotary body, and another one of the electrical conductive member and the brush is connected to the mounting seat. A windmill that uses the rotatable device is also provided.

Abstract: A rotatable lamp holder which comprises lighting elements, a power supply and a motor; the motor has a rotational output shaft; the lighting elements are disposed at a distal end of the rotational output shaft; the rotational output shaft is sleeved with a first PCB and a second PCB; the first PCB is connected to the power supply; the second PCB is connected to the lighting elements; the second PCB is rotatable with the rotational output shaft synchronously in the same direction; the first PCB is arranged with a positive pole coil and a negative pole coil; the second PCB is arranged with a positive pole conductive contact piece which contacts with the positive pole coil and a negative pole conductive contact piece which contacts with the negative pole coil. A solar lamp having the rotatable lamp holder is also provided.

Abstract: A rotatable lamp holder which comprises lighting elements, a power supply and a motor; the motor has a rotational output shaft; the lighting elements are disposed at a distal end of the rotational output shaft; the rotational output shaft is sleeved with a first PCB and a second PCB; the first PCB is connected to the power supply; the second PCB is connected to the lighting elements; the second PCB is rotatable with the rotational output shaft synchronously in the same direction; the first PCB is arranged with a positive pole coil and a negative pole coil; the second PCB is arranged with a positive pole conductive contact piece which contacts with the positive pole coil and a negative pole conductive contact piece which contacts with the negative pole coil. A solar lamp having the rotatable lamp holder is also provided.