light on timer circuit

Light on Timer Circuit:

When the circuit is connected with the power supply then we all know current will flow from the 1K resistor to the transistor's end now, a LED is connected parallelly so, at the first of the circuit the base has no voltage. If we push the Push switch what happens is that the capacitor started charging and stores some charge. Now when we release the push switch the capacitor started discharging through 100k Resistor.
           Here is a simple circuit for turning on a system after a certain time. Just with some simple components like resistors and capacitors and Transistors. You can buy any components from any local store also. For those who want to buy the components from online, I have given links to India as well as anywhere from Globe.

Indian link for Buying:

Amazon.in: 

1.  LED: https://amzn.to/2SdNcdt
2.  Buzzer: https://amzn.to/2S97954
3.  Different values of resistor: https://amzn.to/2t7FxOF
4.  9v Battery: https://amzn.to/2GcseVX
5. 9v Battery Clip: https://amzn.to/2TwOvkj
6. BC548B NPN Transistor: https://amzn.to/2SaC15i

International links for Buying:

Bangood.com:

1.  LED: https://www.banggood.in/custlink/3mDvySETET
2.  Buzzer: https://www.banggood.in/custlink/Gv3GRIhuJr
3.  Different values of resistor: https://www.banggood.in/custlink/KDvGYIdTJt
4. 9v Battery: https://www.banggood.in/custlink/DKDvyZh1FJ
5. 9v Battery Clip: https://www.banggood.in/custlink/Km33E8h7JI
6. BC548B NPN Transistor: https://www.banggood.in/custlink/mKmvh8ywVK

Amazon.com:

1.  LED: https://amzn.to/2MTAwSR
2. Buzzer: https://amzn.to/2t9SszE
3.  Different values of resistor: https://amzn.to/2t9CO7w
4.  9v Battery: https://amzn.to/2TvDCip
5. 9v Battery Clip: https://amzn.to/2t7OV4Q
6. BC548B n-p-n Transistor: https://amzn.to/2GrRkza

Watch this YouTube Video for more information:

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Here are the schematics for the project:

How the circuit works?

The circuit is very easy to understand. This is based on a simple transistor's circuit.

1. When the circuit is connected with the power supply then we all know current will flow from the 1K resistor to the transistor's end now, a LED is connected parallelly so, at the first of the circuit the base has no voltage. So it means that transistor will not be conductive so it means that transistor's collector and the emitter pin have no dynamic connections so it means that Transistor's collector and the emitter pin acts as an open circuit. As we know the LED connected parallelly so it means that at the first of the circuit the current will flow from the 1k resistor the LED and to the GND.
2. If we push the Push switch what happens is that the capacitor started charging and stores some charge. Now when we release the push switch the capacitor started discharging through 100k Resistor. The voltage came to the transistor's base so it means that the transistor became conductive. So Current will flow from transistor's collector to emitter, in this case, the LED will not run because the current will always frow from the shortest path so If it goes from the LED the. It will be a resistive path so it will only flow from the Transistor, as a result, the voltage comes through a 1k resistor and came to virtual GND. The current flows from the resistor now dissipate through heat.  This process will work until the capacitor's charge fully discharges.
3. When the capacitor is fully discharged then no current will flow from the transistor si it means that the Transistor Will not more be conductive as a result the Transistor became off as result the process will be repeated once more the LED will run because of 1K resistor.
4. This process will be followed repeatedly. In this Circuit, we don't have utilized any type of microcontroller, as a result, the making cost of this circuit will be very low.

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