---
# System prepended metadata

title: Electronic Circuit Experiment
tags: [Experiment]

---

# Light-Controlled Lamp


## Project Explanation
The project involves creating a light-controlled lamp, where the intensity of light is used to control the switching on and off of the lamp. The goal is to achieve energy savings by only turning on the lamp when there is insufficient natural light.

## Motivation
Traditional streetlights have fixed schedules, turning off in the morning and on at night. However, factors such as varying sunset times and cloud cover make it challenging to have a uniform lighting schedule. The motivation is to divide the streetlights into multiple zones, each equipped with a light sensor to control the lamps based on the detected light intensity. This approach ensures illumination when needed and reduces unnecessary power consumption.

## Used IC Explanation
- **Variable Resistor:** Controls the light intensity at the moment the lamp is on.
- **Photoresistor (LDR):** Varies resistance based on ambient light. Controls the direction of current flow.
- **Transistor (S8050):** Acts as a switch and power amplifier.
- **Diode (connected in parallel with the relay):** Protects the relay.
- **Resistor (connected in series with the LED):** Protects the LED.
- **LED (Light Emitting Diode):** Simulates the streetlight.
- **Relay (6V):** A current-controlled switch. When energized, forms a circuit with the LED.

## Detailed Circuit Diagram
![Screenshot 2024-01-21 at 22.03.54](https://hackmd.io/_uploads/SkaHc_5tp.png)


## Product Explanation
![Screenshot 2024-01-21 at 22.04.11](https://hackmd.io/_uploads/r1HLq_9F6.png)
![Screenshot 2024-01-21 at 22.04.23](https://hackmd.io/_uploads/Hk9Lcdcta.png)


When the light becomes dim, the resistance of the photoresistor increases. Current flows towards the transistor, turning it on. The current then flows to the fifth pin of the relay, making the fourth pin positive. The potential difference causes the relay's main coil to generate a magnetic effect, pulling the electromagnetic iron, which was originally leaning against the normal open second pin, to the third pin. This allows the current flowing from the first pin to exit through the third pin, forming a circuit, and the LED lights up.

## Reflection
Starting the experiment, the instruments on the table seemed unfriendly, and identifying resistors by color codes was slow. However, over time, I became more familiar with the equipment. The experiments proceeded smoothly, except for the waveform circuit experiment, where I struggled due to lack of understanding. Reviewing the material later helped me grasp the concept.

Towards the end of the semester, nervousness arose due to classmates' speculations about the final exam questions. The final project initially felt challenging, but as I learned the component principles online, I designed a circuit that I was satisfied with. Reflecting on the project, I regret not making the circuit more complex. The semester provided a learning experience, and I look forward to the Digital Systems Experiment in the second year.