Circuit Documentation

Summary

This circuit is a light-dependent LED driver. It uses a Light Dependent Resistor (LDR) to sense ambient light levels and a BC547 transistor to control the LED. When the ambient light level drops below a certain threshold, the LED will turn on. The circuit is powered by a 9V battery.

Component List

1. BC547 Transistor

   • Description: NPN Bipolar Junction Transistor
   • Pins: Collector, Base, Emitter

2. 9V Battery

   • Description: Power source
   • Pins: Positive (+), Negative (-)

3. Resistor (470 Ohms)

   • Description: Limits current to the LED
   • Pins: Pin 1, Pin 2
   • Properties: Resistance: 470 Ohms

4. Resistor (100k Ohms)

   • Description: Forms a voltage divider with the LDR
   • Pins: Pin 1, Pin 2
   • Properties: Resistance: 100k Ohms

5. Photocell (LDR)

   • Description: Light-dependent resistor
   • Pins: Pin 0, Pin 1

6. LED (Red)

   • Description: Light Emitting Diode
   • Pins: Anode, Cathode

Wiring Details

BC547 Transistor

• Collector: Connected to the anode of the LED.
• Base: Connected to Pin 2 of the 100k Ohm resistor and Pin 1 of the LDR.
• Emitter: Connected to Pin 0 of the LDR and the negative terminal of the 9V battery.

9V Battery

• Positive (+): Connected to Pin 1 of the 470 Ohm resistor and Pin 1 of the 100k Ohm resistor.
• Negative (-): Connected to Pin 0 of the LDR and the emitter of the BC547 transistor.

Resistor (470 Ohms)

• Pin 1: Connected to the positive terminal of the 9V battery.
• Pin 2: Connected to the cathode of the LED.

Resistor (100k Ohms)

• Pin 1: Connected to the positive terminal of the 9V battery.
• Pin 2: Connected to the base of the BC547 transistor and Pin 1 of the LDR.

Photocell (LDR)

• Pin 0: Connected to the emitter of the BC547 transistor and the negative terminal of the 9V battery.
• Pin 1: Connected to Pin 2 of the 100k Ohm resistor and the base of the BC547 transistor.

LED (Red)

• Anode: Connected to the collector of the BC547 transistor.
• Cathode: Connected to Pin 2 of the 470 Ohm resistor.

Code

No microcontroller code is used in this circuit.