This smoke detector circuit diagram is based on the SD2 CMOS Photo-Electric Smoke Detector Integrated Circuit manufactured by Supertex INC and include almost all needed components to build a very simple and high efficiency smoke detector project .
The LED predriver output pulses an external transistor which in turn, switches on the infrared light emitting diode at a very low duty cycle. The desired IR LED pulse period is determined by the value of the external timing resistor. The Smoke Sensitivity is adjustable through a trimmer resistor which varies the IR LED pulse width. The light sensing element is a silicon photovoltaic cell which is held at near zero bias to minimize leakage currents. The circuit can detect signals as low as 1 mV and generate an alarm. The IR LED pulse repetition rate increases when smoke is detected.
The IR diode can be RCA Type SG 1010A or Spectronics Type SE 5455-4 Clairex and the IR Photo detector can be Vactec VTS4085 .
Because the SD2 CMOS Photo-Electric Smoke Detector IC is designed for use in low power, battery operated, consumer applications it needs a 9 volts DC power supply (or a 9 volts battery ).
The LED predriver output pulses an external transistor which in turn, switches on the infrared light emitting diode at a very low duty cycle. The desired IR LED pulse period is determined by the value of the external timing resistor. The Smoke Sensitivity is adjustable through a trimmer resistor which varies the IR LED pulse width. The light sensing element is a silicon photovoltaic cell which is held at near zero bias to minimize leakage currents. The circuit can detect signals as low as 1 mV and generate an alarm. The IR LED pulse repetition rate increases when smoke is detected.
The IR diode can be RCA Type SG 1010A or Spectronics Type SE 5455-4 Clairex and the IR Photo detector can be Vactec VTS4085 .
Because the SD2 CMOS Photo-Electric Smoke Detector IC is designed for use in low power, battery operated, consumer applications it needs a 9 volts DC power supply (or a 9 volts battery ).
IPC/AMM are confusing. Don't want exact dimension but atleast operation mechnism. No confidential data required.
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