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This is a simple alarm circuit in the bc547 transistor project. we can easily make a Fire Alarm out of it.ģ.) bc547 transistor project -Alarm Circuit

The operating temperature of the BC547 Transistor is up to 150 degrees C, so it can be perfectly used at high temperature as Heat Sensor.

The Base-Emitter voltage (V BE) drops approx. The temperature dependency of a transistor can be understood by the formula presented here. Set the Potentiometer at the position, where a slight rotation will start a dim illumination in LED. Working of the circuit is very simple when the temperature increases to the level which crosses the threshold value set by Potentiometer, the collector current increase, and LED starts illuminating slowly. the sensitivity of the circuit is adjusted by rotating the knob. Transistor BC547 is used as a Heat Sensor, As the temperature of the PN junction increase, the transistor starts conducting.ĭiode 1N4148and a variable resistor of 1k ohm is used to set a threshold level for the sensitivity of heat. This Heat Sensor is very simple and effective. This circuit requires fewer easily available components. Here is a very simple Temperature Sensor Circuit or Heat Sensor Circuit. The second application is a simple fire detector. 2.)bc547 transistor project- Simple fire detection system: The circuit will amplify the voice input fed by the condenser mic. Here we have placed a MIC in place of the AUX jack. The amplification of the input signal from MIC: In this way, it converts Electric energy into the audio output. Due to this larger current from the 9v battery? passes thought the speaker. We are applying a voltage at its base from the audio input signal by AUX cable. In this circuit, the transistor allows a larger current to flow when we apply smaller voltage at its base. It is used as a filter to block out the DC component of the input signal. Here the capacitor C1 is a coupling capacitor. This is the simplest circuit for amplifier The Circuit diagram for the amplifier of the AUX output of the Mobile Phone is as shown: We have used this amplifier circuit for amplifying the AUX output of a Mobile phone or mic. To use Bjt as an amplifier, emitter-base junction is forward biased whereas the collector-base junction is reverse biased. When the input voltage is applied at emitter and base terminal, some amount of current starts to flow from base to the emitter which controls the current at the collector terminal. The inputted signal is amplified at the base and then gets transferred to the emitter. It is best operated in the active region.īC547 is biased in such a way that it is partially on for all the applied inputs. For proper operation of the transistor, A fixed DC voltage is required. Supplying a proper DC voltage to the transistor is known as the biasing of transistor. The maximum current gain of this transistor is around 800. The current flowing from base to the emitter controls the current flowing through the collector.īC547 is usually used for amplification and switching purposes. In transistors, a small amount of current at the base terminal controls a larger amount of current at the emitter and collector.īC547 has three terminals as in other transistors. The use of a transistor is to transfer the resistance. The word transistor means of two words, transfer and resistor. It is widely used for power amplification and switching. Bc-547 is an NPN bipolar junction transistor(BJT). Here are the Top 5 DIY bc547 transistor project for you.