Abstract: A kind of two-wire direct current electric fan system with countable rotation rate, which is used in the systemic radiating electric fan of an information processing device. It contains a two-wire direct current electric fan, a rotation rate inducing circuit, a pulse amplifying circuit and a counting circuit. The system of the invention utilizes the rotation rate inducing circuit of the two-wire direct current electric fan, which is installed on the motherboard of the information processing device. It converts the rotation of the electric fan into a pulse, and amplifies the pulse to a detectable level. The rotation rate of the electric fan is then determined by the counting circuit on the motherboard. The invention uses a two-wire electric fan to achieve the objective of rotation rate counting.

Abstract: A pulse charger that utilizes a charging strategy to compensate the physical characteristic of a secondary battery. That is, electrical current is supplied is based on the electric voltage of a secondary battery. According to the above concept, the pulse charger of the invention mainly contains: an on/off switch, a switch control circuit and a counter control circuit. The counter control circuit connects to the secondary battery to generate a resonant frequency that is in proportion to the electric voltage. The switch control circuit utilizes the resonant frequency output to control the on/off switchcounter control circuit for switching between the power and the secondary battery.