Abstract: An anti-pop device for audio amplifier is suitable for outputting signals to a speaker to produce sound waves. The audio amplifier comprises a pre-processing unit, a filter and a voltage level detection unit electrically connected to the pre-processing unit. The voltage level detection unit detects the supply voltage. As the supply voltage is lower than a predetermined value, the voltage level detection unit outputs a signal to the pre-processing unit for lowering the audio volume so that a pop noise caused by circuit malfunction resulted from excessively-low supply voltage can be prevented.

Abstract: The present invention discloses a catalyst useful in selective oxidation of carbon monoxide (CO) contained in a hydrogen-rich reformate gas. The catalyst is a zeolite carrying Pt, Ru or alloys thereof. Pt or Ru is deposited on the zeolite by incipient wetness impregnation with an aqueous solution. The reformate gas having a reduced CO concentration can be introduced to a fuel cell as a fuel.