As shown in the figure is a controllable integration circuit. The circuit has a controllable integrator with zero reset, hold and different integration time constants. The analog switch is CH300 and the operational amplifier is F007. The R and C1, C2 values ​​in the figure can be configured as needed. The different control states of the four analog switches allow the circuit to perform different functions. Smoke Detector, interlinked smoke detector, conventional smoke detector Smoke Detector, interlinked smoke detector, conventional smoke detector Ningbo Multitasking Electronic Co.,Ltd , https://www.smartmultesic.com