Showing posts with label heat. Show all posts
Showing posts with label heat. Show all posts
Thursday, November 13, 2014
Heat Sensor Circuit Diagram
This simple heat sensor circuit could senses heat from various electronics device like computer, amplifier etc. and generate warning alarm. It could senses heat from environment also, but here I mention “electronics device” because it is being using mostly in electronic device to protect them from overheat.
Circuit diagram of heat sensor:
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| Fig-1: Schematic Circuit Diagram Of Heat/Temperature Sensor |
Thermistor, 110 Ohms:
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| Fig-2: 110 Ohms Thermistor |
As it is a heat sensor circuit, here a thermistor is used as a heat sensor. It is a thermal measurement device and has a variety of usages including temperature sensor/ heat sensor. The thermistor used in this circuit is a NTC (Negative Temperature Coefficient) type thermistor. When temperature increases, its resistance goes decrease. Therefore, NTC thermistor’s resistances are inverse of temperature.
Circuit Description:
You have seen, in this simple circuit diagram of heat sensor, a few number of components is used including a BC548 transistor, a 110 ohms thermistor etc.- BC548: BC548 is a TO-92 type NPN transistor, as its alternative you can use 2N2222, BC238, BC548, BC168, BC183 etc. they all have almost same characteristic.
- 110 Ohms Thermistor: A 110 Ohms thermistor is used to detecting heat. I have told already about it.
- Buzzer: A buzzer is used with +9V and collector of transistor. When the temperature/ heat exceeds a certain level then it make an alarm.
- 4.7V Zener diode: It is used to limit the emitter current of BC548.
- 9V Battery: A 9V battery is used as a single power source.
- R1, R2: A 3.3K 1/4w resistor is used as R1 and 100 ohms 1/4w as R2.
- Switch: Here in this circuit the switch used is a simple SPST switch. You can either use the switch or not, choice is yours. It is not mandatory.
Wednesday, August 27, 2014
Heat Sensor Fire Detector Pyroelectric
These sensors form of Lithium Tantalate pyroelectric parallel opposed dual element high gain detector with integrated analog signal processing. These sensors can detect heat changes from -40 to +70 degrees Celsius without change siginfikan of noise and sensitivity.
To use heat sensor pyroelectric detectors Eltec E442-3, it can take a kind of cone is covered with a fresnel lens to focus the direction of the infrared ray IR. Heat sensors then pyroelectric detectors Eltec E442-3 inserted into the cone is then connected to the microcontroller. Analog output value signals which when detects heat, the sensor will cause a drastic change in output voltage.
Monday, August 18, 2014
Heat Detector Alarm using UM3561
A very simple heat detector alarm electronic project can be designed using the UM3561 sound generator schema and some other common electronic parts . This heat detector electronic schema project uses a complementary pair comprising npn and pnp transistor to detect heat Collector of T1 transistor is connected to the base of the T2 transistor , while the collector of T2 transistor is connected to RL1 relay T3 and T4 transistors connected in darlington configuration are used to amplify the audio signal from the UM3561 ic.
When the temperature close to the T1 transistor is hot , the resistance to the emitter –collector goes low and it starts conducting . In same time T2 transistor conducts , because its base is connected to the collector of T1 transistor and the RL1 relay energized and switches on the siren which produce a fire engine alarm sound. This electronic schema project must be powered from a 6 volts DC power supply , but the UM3561 IC is powered using a 3 volt zener diode , because the alarm sound require a 3 volts dc power supply. The relay used in this project must be a 6 volt / 100 ohms relay and the speaker must have a 8 ohms load and 1 watt power.
Streampowers
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