Hello viewers, in this tutorial we will learn about how to make a Noise detector circuit using a single transistor
NOISE DETECTOR CIRCUIT can also be called as SOUND DETECTOR CIRCUIT. It is used to detect HIGH DECIBEL AND HIGH PITCH NOISY SOUND WAVES and is composed of MIC, transistor, resistors, battery and LED.
COMPONENTS REQUIRED FOR NOISE DETECTOR CIRCUIT USING A SINGLE TRANSISTOR
- 100K Resistor
- 470Ω Resistor
- BC547 Transistor
- 9 Volt Battery
- Battery Clip
- Bread Board
MIC is an electronic device which converts the audio signal into electrical signal in the form of analog signal. Its basic function is to detect the interference produced in air in the form of compression and rarefaction i.e. sound and converts it into the electrical signal. Inside MIC there is a filament like structure made of very thin metallic paper like thing in the form of ribbon shape which vibrates whenever it comes in the contact of sound wave and that vibration generates the electrical signal which afterward gets converted into audible sound with the help of circuits and speaker. There are many different-different types of speakers varying in shape size and structure. Ex- Condenser MIC, Electret MIC etc. Here in our case we are using condenser MIC.
Transistor is a semiconductor device which is basically of two types NPN and PNP. In PNP transistor, N-type semiconductor is sandwiched between two P-type semiconductors and in NPN transistor, P-type semiconductor is sandwiched between two N-type semiconductors. Transistors have three legs namely COLLECTOR, BASE and EMITTER. Here in this circuit we are using a BC547 transistor which is a very commonly used NPN transistor. You can use any type of NPN transistor such as BC548, BC549 etc. Its operation is very simple; whenever a current is applied in its base then the barrier between the collector and the emitter gets decreased and charge starts flowing from collector to emitter by which both terminals gets shorted internally.
Resistor is an electronic device which opposes the flow of current through it. It has two terminals and there is no polarity so it can be operated in both forward and reverse direction. Its value is characterized by its color of 4 bands present on it. Value of resistance is calculated by color coding. Here in our case we are using a 100k and 470Ω resistor.
LED stands for Light Emitting Diode. It is a normal p-n junction diode which emits light whenever a current is passed through it. It is available in market in many different colors and of different power ratings. It has two terminals namely anode and cathode where longer one is anode and shorter one is cathode. It is operated in forward biased direction. Its operating voltage is 1.5V
Battery is a voltage source device which stores charge and energy. There are many different types of batteries of different-different types of voltage ratings which are available in the market such as 1.5V, 3.7V, 4V, 6V, 9V, 11.7V, 12V etc. There are different types of batteries such as Lead-Acid battery, Lithium-Ion battery, Li-Po battery etc. Here in our case we are using a 9V battery.
Battery Clip is used to connect the battery from the circuit to the Bread Board. It has two wires in which Red one is +ve and Black one is –ve.
Bread Board is nothing but a trainer board which provides convenience to the hobbyists. In bread board you can build up any circuit without any soldering. The thing you need is just to plug and play. It has dotted bread like pores in it in which you can insert the legs of your any electronic components such as resistor, transistor, diode etc for the operation.
MECHANISM AND WORKING OF NOISE DETECTOR
It’s an extremely simple circuit made with very few basic components, as it is a NOISE DETECTOR CIRCUIT so its function is to detect noise in the surrounding as it detects the high decibel and high pitch sound. Whenever there is a NOISE then the MIC detects that noise and converts it in the electrical signals and sends that signal to the transistor which further activates the LED. In other words the current coming from the 100K resistor to the base of the transistor wants to enter to transistor but it can’t as the base is connected to MIC which is draining all the current and the current coming from 100k resistor goes to the ground and gets drained through the MIC and transistor remains in the of state and hence LED also but as soon as the NOISE is detected by the MIC then the MIC produces pulsating signals which further goes to transistor and activates and deactivates the transistor momentarily which further produces a pulsating signal and LED connected with the transistor starts blinking which shows that there is some noise. This circuit has a very wide and useful application for the areas where the hospitals and schools are located and where noise and sound are strictly prohibited. By this circuit anyone can detect that there is noise without going to that place and can also control it by taking necessary step.
CIRCUIT DIAGRAM OF NOISE DETECTOR CIRCUIT USING A SINGLE TRANSISTOR
WIRING AND CONNECTION OF NOISE DETECTOR CIRCUIT USING A SINGLE TRANSISTOR
STEP 1 OF NOISE DETECTOR CIRCUIT USING A SINGLE TRANSISTOR:
Connect battery clip to the Bread Board.
STEP 2 OF NOISE DETECTOR CIRCUIT USING A SINGLE TRANSISTOR:
Plug the transistor into the breadboard and connect the emitter to the ground.
STEP 3A OF NOISE DETECTOR CIRCUIT USING A SINGLE TRANSISTOR:
Connect one end of the 470R resistor to the collector of the transistor and other end to the –ve of LED and connect +ve of LED to the +ve supply.
STEP 3B OF NOISE DETECTOR CIRCUIT USING A SINGLE TRANSISTOR:
STEP 4 OF NOISE DETECTOR CIRCUIT USING A SINGLE TRANSISTOR:
Connect -ve end of the MIC to the emitter of the transistor and +ve end of the MIC to the base of the transistor.
STEP 5A OF NOISE DETECTOR CIRCUIT USING A SINGLE TRANSISTOR:
Connect 100k resistor to the base of the transistor from +ve supply and connect the battery and check whether the circuit is working or not by blowing air to the MIC (as it behaves as a NOISE).
STEP 5B OF NOISE DETECTOR CIRCUIT USING A SINGLE TRANSISTOR:
You just made a noise detector now you can detect a noise and find a peaceful place to relax.
This is Enamul Hassan, an Electrical and Electronics Engineer. I love discovering new things. I share my knowledge in this blog.