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Hello everyone! This circuit is a Dark Sensor Circuit. Obviously, in this software, there is no LDR. For those who aren't familiar with the LDR/Photoresistor, it is a type of Resistor that changes it's resistance based on the Light it receives. If the Light Level increases, the Resistance decreases and Vice Versa when it's dark. I substituted a Regular Resistor in place of a Photoresistor. To act like it is Dark and the LDR receives little Light, Increase the Resistance of the 6k Resistor. This is because when an LDR receives little light, it increases it's resistance. You will see that the LED will light up once you increase the resistance of the 6k Resistor. Also, I recommend to take a look at the Graph of the Collector of the Transistor. The Collector is the Output of a Transistor. You will see how the Output Voltage changes as you increase the "LDRs" Resistance.
How it works is the LDR is Connected to a 47k-100k Resistor. The LDR is connected to GND and the 47k Resistor is Connected to +12v (You can use 5-12v). When 2 Resistor each connected to opposite sides of a Battery are connected, it forms a Voltage Divider. When one Resistor from those Two changes it's Resistance, the Output voltage will be different. Same thing with the LDR; it is changing it's Resistance. That Voltage goes to the Base of the Transistor (See below for what an NPN Transistor is) which gets amplified into an LED. And that voltage that is changing depending on the Light goes to that LED from the Transistor
A Transistor is an Electronic component that amplifies a Signal/Voltage. It takes that input at the Middle pin or the BASE, Gets Power (Usually GND, but not always) from the Emitter, and the Output is at the Collector. To use a Transistor, all you have to do is Connect the Emitter to GND, the Base to the Input (The Voltage Divider for me) and connect the Collector to the LED or whatever you are using as an Output
I hope you enjoyed and found this helpful! Please Bookmark this for further reference and leave a comment! Thank You!
We are using a BC547 NPN Transistor for this Circuit
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