Detector circuit
This is an Overheat Detector Alarm Switch using the Temperature Sensor IC LM35. The core of this overheat detector (fire alarm) circuit is a precision integrated temperature sensor, the LM35 (IC1), which provides an accurately linear and directly proportional output in millivolts over the temperature range of 0 to +155 degrees Celsius. This device can be used as part of fire smoke detectors but should not be relied upon as a home fire alarm system. The output from the LM35 is connected to the non-inverting input of a comparator configured with a CA3130 op-amp (IC2). A voltage divider network consisting of R3 and P1 sets the threshold voltage at the inverting input of the op-amp. This threshold voltage establishes the adjustable temperature trip level at which the circuit activates. When the measured temperature surpasses the user-defined threshold, the comparator outputs a high signal of approximately 2.2 V, which forward biases transistor T1. This activation also turns on T2, supplying the oscillator circuit around IC3 with sufficient voltage to operate. The 555 timer, set up in astable mode, directly drives an active piezoelectric buzzer (Bz1) to generate a loud alert. Components R7, R8, and C4 determine the on/off rhythm of the sounder. A transistor-based relay driver can be activated from the emitter of T1 (TP1). Additionally, replacing the piezo sounder with an appropriate relay allows for the switching of high-power flashers, sirens, or horns operating on AC mains supply.
This is a Water Level Sensor and Alarm Circuit using the CD4066. This circuit not only indicates the water level in the tank but also triggers an alarm when the tank is full. When the tank is empty, the wires are open-circuited, and the 180K resistors pull the switch open, turning off the LEDs. As water begins to fill the tank, the first wire connected to the reservoir (S1) and the positive supply are shorted by water, closing S1 and turning LED1 on. As the water continues to rise, LEDs 2, 3, and 4 gradually light up. When the tank is full, the water saturates the base of the BC148 transistor, turning on the buzzer. An SPST switch is included to turn off the alarm.
Using the IC RE46C140, a smoke detector alarm can be designed with only a few external components. The RE46C140 is a low-power CMOS photoelectric smoke detector IC that encompasses all necessary features for a photoelectric smoke detector project. An internal oscillator pulses power to the smoke detection circuitry for 100 microseconds every 10 seconds to minimize standby current. If smoke is detected, the detection rate increases to confirm an alarm condition. An internal 10-minute timer can be utilized for reduced sensitivity mode. In standby mode, the LED pulses on for 10 milliseconds every 43 seconds, while in a local alarm or during a push-to-test scenario, the LED pulse frequency increases to once every 0.5 seconds. In the remote alarm condition, the LED remains inactive. During timer mode, the LED pulses on for 10 milliseconds every 10 seconds. A comparator assesses the output from the photo amplifier against an internal reference voltage. If the required number of consecutive smoke conditions is detected, the device activates the local alarm and the horn. The bidirectional IO pin facilitates the interconnection of multiple detectors. During a local alarm, this pin is driven high through a constant current source, and shorting this output to ground does not cause excessive current. The IO pin is disregarded as an input during a local alarm. Conductance, which is the reciprocal of resistance, varies with temperature, volume, and the separation distance of the measurement probes. For instance, tap water has a conductance of approximately 50 µS/cm at 25 °C, equating to about 20kΩ/cm at that temperature. This circuit is capable of triggering with any fluid possessing a resistance.This is Overheat Detector Alarm Switch using Temperature Sensor IC LM35 Electronic Suite Diagram, at the heart of this overhead detector (fire alarm) circuit is a precision integrated temperature sensor type LM35 (IC1), which provides an accurately linear and directly proportional output in mV, over the zero to +155 degrees C temperature range. Th is can be used as part of fire smoke detectors but do not use it as a home fire alarm system. Here the output of the LM35 is applied to the non-inverting input of a comparator wired around a CA3130 opamp (IC2). A voltage divider network R3-P1 sets the threshold voltage, at the inverting input of the opamp. The threshold voltage determines the adjustable temperature trip level at which the circuit is activated.
When the measured temperature exceeds the user-defined level, the comparator pulls its output High to approx. 2. 2 V causing transistor T1 to be forward biased instantly. T2 is also switched on, supplying the oscillator circuit around IC3 with sufficient voltage to start working.
The 555 set up in astable mode directly drives active piezoelectric buzzer Bz1 to raise a loud alert. Components R7, R8 and C4 determine the on/off rhythm of the sounder. A transistor based relay driver may be driven off the emitter of T1 (TP1). Similarly, replacing the piezo sounder with a suitable relay allows switching of high-power flashers, sirens or horns working on the AC mains supply.
This is Water Level Sensor and Alarm Circuit using CD4066 Circuit Schematic, forcircuit not only indicates the amount of water in the tank head, but also gives an alarm when the tank is full. If the water is empty the wires in the tank are open circuit and the 180K resistors pulls the switch to open the little switches and LEDs are off.
When the water begins to fill the first wire connected to the reservoir in the S1 and the + supply are shorted by water. This closes the S1 and turns the LED1 ON. As the water further into the tank, LEDS2, 3 to 4 pm light gradually filled. If the water is full, the base of the transistor BC148 is pulled up with water and saturate the transistor, turning the buzzer ON.
The SPST switch has to be opened to turn off the ringer. Using the IC RE46C140 integrated circuit you can design smoke detector alarm using few external electronic components. The IC RE46C140 is a low power CMOS photoelectric type smoke detector IC that will provide all the required features for a photoelectric type smoke detector project.
An internal oscillator strobes power to the smoke detection circuitry for 100us every 10 seconds to keep standby current to a minimum. If smoke is sensed the detection rate is increased to verify an alarm condition. An internal 10 minute timer can be used for a reduced sensitivity mode. In standby the LED is pulsed on for 10mS every 43 seconds. In a local alarm condition or the push to test alarm the LED pulse frequency is increased to once every.
5 seconds. In the case of a remote alarm the LED not active. In the timer mode of operation the LED is pulsed on for 10mS every 10 seconds. A comparator compares the photo amp output to an internal reference voltage. If the required number of consecutive smoke conditions is met the device will go into local alarm and the horn will be active. The bidirectional IO pin allows interconnection of multiple detectors. In a local alarm condition this pin is driven high immediately through a constant current source. Shorting this output to ground will not cause excessive current. The IO is ignored as an input during a local alarm. Conductance is the reciprocal of resistance. The conductance of fluids vary with temperature, volume and separation distance ofthe measurement probes.
Tap water has a conductance of about 50 uS / cm measured at 25 °C. This is 20k/cm at 25 °C. See this site for more details about the conductance of fluids. This circuit will trigger with any fluid with a resista 🔗 External reference
This is a Water Level Sensor and Alarm Circuit using the CD4066. This circuit not only indicates the water level in the tank but also triggers an alarm when the tank is full. When the tank is empty, the wires are open-circuited, and the 180K resistors pull the switch open, turning off the LEDs. As water begins to fill the tank, the first wire connected to the reservoir (S1) and the positive supply are shorted by water, closing S1 and turning LED1 on. As the water continues to rise, LEDs 2, 3, and 4 gradually light up. When the tank is full, the water saturates the base of the BC148 transistor, turning on the buzzer. An SPST switch is included to turn off the alarm.
Using the IC RE46C140, a smoke detector alarm can be designed with only a few external components. The RE46C140 is a low-power CMOS photoelectric smoke detector IC that encompasses all necessary features for a photoelectric smoke detector project. An internal oscillator pulses power to the smoke detection circuitry for 100 microseconds every 10 seconds to minimize standby current. If smoke is detected, the detection rate increases to confirm an alarm condition. An internal 10-minute timer can be utilized for reduced sensitivity mode. In standby mode, the LED pulses on for 10 milliseconds every 43 seconds, while in a local alarm or during a push-to-test scenario, the LED pulse frequency increases to once every 0.5 seconds. In the remote alarm condition, the LED remains inactive. During timer mode, the LED pulses on for 10 milliseconds every 10 seconds. A comparator assesses the output from the photo amplifier against an internal reference voltage. If the required number of consecutive smoke conditions is detected, the device activates the local alarm and the horn. The bidirectional IO pin facilitates the interconnection of multiple detectors. During a local alarm, this pin is driven high through a constant current source, and shorting this output to ground does not cause excessive current. The IO pin is disregarded as an input during a local alarm. Conductance, which is the reciprocal of resistance, varies with temperature, volume, and the separation distance of the measurement probes. For instance, tap water has a conductance of approximately 50 µS/cm at 25 °C, equating to about 20kΩ/cm at that temperature. This circuit is capable of triggering with any fluid possessing a resistance.This is Overheat Detector Alarm Switch using Temperature Sensor IC LM35 Electronic Suite Diagram, at the heart of this overhead detector (fire alarm) circuit is a precision integrated temperature sensor type LM35 (IC1), which provides an accurately linear and directly proportional output in mV, over the zero to +155 degrees C temperature range. Th is can be used as part of fire smoke detectors but do not use it as a home fire alarm system. Here the output of the LM35 is applied to the non-inverting input of a comparator wired around a CA3130 opamp (IC2). A voltage divider network R3-P1 sets the threshold voltage, at the inverting input of the opamp. The threshold voltage determines the adjustable temperature trip level at which the circuit is activated.
When the measured temperature exceeds the user-defined level, the comparator pulls its output High to approx. 2. 2 V causing transistor T1 to be forward biased instantly. T2 is also switched on, supplying the oscillator circuit around IC3 with sufficient voltage to start working.
The 555 set up in astable mode directly drives active piezoelectric buzzer Bz1 to raise a loud alert. Components R7, R8 and C4 determine the on/off rhythm of the sounder. A transistor based relay driver may be driven off the emitter of T1 (TP1). Similarly, replacing the piezo sounder with a suitable relay allows switching of high-power flashers, sirens or horns working on the AC mains supply.
This is Water Level Sensor and Alarm Circuit using CD4066 Circuit Schematic, forcircuit not only indicates the amount of water in the tank head, but also gives an alarm when the tank is full. If the water is empty the wires in the tank are open circuit and the 180K resistors pulls the switch to open the little switches and LEDs are off.
When the water begins to fill the first wire connected to the reservoir in the S1 and the + supply are shorted by water. This closes the S1 and turns the LED1 ON. As the water further into the tank, LEDS2, 3 to 4 pm light gradually filled. If the water is full, the base of the transistor BC148 is pulled up with water and saturate the transistor, turning the buzzer ON.
The SPST switch has to be opened to turn off the ringer. Using the IC RE46C140 integrated circuit you can design smoke detector alarm using few external electronic components. The IC RE46C140 is a low power CMOS photoelectric type smoke detector IC that will provide all the required features for a photoelectric type smoke detector project.
An internal oscillator strobes power to the smoke detection circuitry for 100us every 10 seconds to keep standby current to a minimum. If smoke is sensed the detection rate is increased to verify an alarm condition. An internal 10 minute timer can be used for a reduced sensitivity mode. In standby the LED is pulsed on for 10mS every 43 seconds. In a local alarm condition or the push to test alarm the LED pulse frequency is increased to once every.
5 seconds. In the case of a remote alarm the LED not active. In the timer mode of operation the LED is pulsed on for 10mS every 10 seconds. A comparator compares the photo amp output to an internal reference voltage. If the required number of consecutive smoke conditions is met the device will go into local alarm and the horn will be active. The bidirectional IO pin allows interconnection of multiple detectors. In a local alarm condition this pin is driven high immediately through a constant current source. Shorting this output to ground will not cause excessive current. The IO is ignored as an input during a local alarm. Conductance is the reciprocal of resistance. The conductance of fluids vary with temperature, volume and separation distance ofthe measurement probes.
Tap water has a conductance of about 50 uS / cm measured at 25 °C. This is 20k/cm at 25 °C. See this site for more details about the conductance of fluids. This circuit will trigger with any fluid with a resista 🔗 External reference
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