Abstract: A method for measuring intrinsic capacitance of a MOS device is provided. The MOS device includes a first terminal, a second terminal, a third terminal and a fourth terminal. First, provide a first input signal to the second terminal and ground the third terminal and fourth terminal. Then, charge the first terminal and measure a first current required for charging the first terminal. Afterward, provide a second input signal to the second terminal, ground the third terminal and the fourth terminal, and measure a second current required for charging the first terminal, wherein the first input signal and the second input signal have the same low level, but different high levels. Finally, determine intrinsic capacitance between the first terminal and the second terminal according to the first current, the second current and a high level difference between the first input signal and the second input signal.

Abstract: A smoke exhauster comprises an enclosure including a fan housing and a flood plate releasably secured thereunder. The enclosure has a plurality of spiral coupling recesses on the top plate for releasable securing the fan housing by a T-shaped fastener. The hood plate has at four corners a sliding catch member positioned in registry with the corresponding locking holes on the enclosure so as to permit the hood plate to be slidingly secured to the enclosure. The hood plate can be suspended from the rear of the enclosure if the sliding catch member on the rear is not intended to be disengaged. This arrangement provides faster and more convenient assembly or disassembly of the smoke exhauster for facilitating a rapid removal of the oil and grime accumulated on them.

Abstract: A smoke exhauster structure comprises an enclosure having a releasably secured lower hood plate and a releasably secured fan housing disposed therein. The hood plate has a pair of spring loaded pivoting catches provided on respective rear corner portions thereof and a pair of protruding tabs on the front edge thereof which overlap and abut a retaining rim provided under the front panel of the enclosure. Each pivoting catch engages a respective locking bar in a rear portion of the enclosure to releasably secure the hood thereunder. The fan housing which surrounds the exhaust fans of the exhauster is releasably secured to the underside of a top plate of the enclosure by a set of latches provided around the periphery thereof. Each latch has a pivoting buckle whose ends are connected to a spring loaded lever, each buckle engages a corresponding hook shaped securing appendage provided on the underside of the top plate.