₹199 – ₹249
- Product Code: LGZK001
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This circuit works as fire alarm circuit. It is based on IR(infra-red) sensors. Fire has lot of IR rays. In the given circuit ir sensor and R2 works as resistance divider network. As the infrared rays falls on sensor its resitance decreases and the value of R2 is fixed. This causes the voltage at pin 3 of operational amplifer to increase.(on its non inverting terminal). If the voltage set at pin2 of the opreational amplifier (LM358) becomes less than the voltage of pin 3 then the output of the op-amp(operational amplifer) becomes high. This is the fundamental principle of operation of any operational-amplifier i.e. if the voltage of non-inverting amplifer becomes higher than the voltage of the inverting amplifier the output becomes high.
The led D1 is used here for indication purpose only. The reistance R1 is used to protect the LED from overcurrent damage. Buzzer is active buzzer(BZ1), whenever its pin1 goes high, it starts beeping.
- Dimensions (cm) LxWxH: 15 x 12 x 5
- Weight (gm): 150