Abstract: A duty cycle detecting circuit for pulse width modulation (PWM). The circuit includes a clock generating circuit, a sampling circuit and a calculation circuit. The clock generating circuit is for generating a clock signal. The sampling circuit receives a PWM signal and the clock signal, samples the PWM signal based on the clock signal, and generates a sampling signal. The calculation circuit is for calculating the duty cycle of the PWM signal based on the sampling signal.

Abstract: This invention discloses a verifying system and method thereof. The verifying system comprises a plurality of objects to be verified and a verifying end. Each of the objects to be verified respectively comprises an identifying code. The verifying end has a database, and the database stores a plurality records of information of the objects respectively corresponding to each of the indentifying codes. When a user utilizes an electronic device to read one of the indentifying codes for making the electronic device connect to the verifying end, the verifying end compares the identifying code with the plurality records of information of the objects to generate an information of verification results which is then transmitted back to the electronic device. Herewith the effect of the present invention being verifying authenticity of the object by the indentifying code is achieved.

Abstract: A refractive fuel concentration detector comprises mainly a light source device and a light-sensing device. The light source device supplies light source incident on the fuel and refracts light source to the light-sensing device such that a plurality of light sensor therein would respectively output a corresponding electrophysical quantity signal based on the light quantity received. Moreover, a circuit means can be used to obtain concentration information of fuel based on the electrophysical quantity signal output by the light sensors and the tag information of those light sensors.