Abstract: The present application relates to a detection circuit for detecting a detector removal fault. The detection circuit comprises: a switching circuit. The switching circuit comprises one or more switching elements; an energy storage element; and a control circuit for controlling the energy storage element to discharge by controlling the one or more switching elements to perform an opening or closing action. The control circuit is configured to cause the energy storage element to discharge based on a first loop if the detector is removed from the diode bases, and to cause the energy storage element to discharge based on the first loop and a second loop including the terminal resistor if the detector is not removed from the diode bases. The control circuit is further configured to detect the detector removal fault based on an output voltage of the area monitoring module during discharge process.

Abstract: The present application provides an optical filter, and a test assembly and method for a smoke detector. The optical filter comprises: a support; and a screen supported by the support, wherein the screen is composed of wires and mesh holes are defined between the wires, and the screen has a first side and a second side opposite to each other; wherein, the smoke detector comprises a light transmitter and a light receiver arranged in vicinity and an light reflector arranged opposite to the light transmitter and the light receiver, such that light emitted by the light transmitter is reflected to the light receiver via the light reflector; and wherein, during testing, the optical filter is arranged in both the light path from the light transmitter to the light reflector and the light path from the light reflector to the light receiver.

Abstract: The present application relates to a boost circuit for driving a light-emitting diode. The boost circuit comprises: a first input terminal operably connected with an external power supply; a second input terminal operably connected with a pulse width modulation signal source; an output terminal operably connected with the light-emitting diode; a first capacitor, a positive electrode of which is coupled with the first input terminal and the output terminal, and a negative electrode of which is coupled with the second input terminal; and a second capacitor, a positive electrode of which is coupled with the positive electrode of the first capacitor and the output terminal, and a negative electrode of which is grounded, wherein, when an applied pulse width modulation signal is at low level, the external power supply charges the first capacitor with a first voltage.

Abstract: A combustible gas sensor module and a combustible gas sensing device. The combustible gas sensor module includes an enclosure including a first end and a second end opposite to each other; a plug connector disposed at the first end of the enclosure for connecting to a sensing device body of a combustible gas sensing device; a sensor unit disposed at the second end of the enclosure for sensing combustible gas; and a circuit board disposed in the enclosure and respectively connected to the plug connector and the sensor unit, with a microcontroller provided thereon.