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Transistor Circuits

Simple 12V Battery Charger Circuit using TIP41 Transistor

Last updated on 3 December 2025 by Admin-Lavi Leave a Comment

This is a Simple 12V Battery Charger Circuit using TIP41 Transistor. It uses one NPN power transistor TIP41 and one 13.8V Zener diode. The circuit is cheap, easy and safe for charging 12V lead acid battery. This circuit works for small 7Ah to 20Ah batteries. It is a good circuit for learning basic battery charging. […]

Filed Under: Battery Charger Circuits, Transistor Circuits

Natural Bird Sound Generator Circuit using Transistors

Last updated on 1 December 2025 by Admin-Lavi Leave a Comment

This is a small Natural Bird Sound Generator Circuit using Transistors. The circuit uses two BC547 transistors, some resistors, capacitor and a speaker. It is simple for beginners and works on low voltage like 3V to 9V. Circuit is good for toys, hobby projects, alarms and for school projects. Circuit Working: Parts List: Item Value […]

Filed Under: Audio Circuits, Transistor Circuits

Laser Security Alarm Circuit using LDR and BC547 Transistors

Last updated on 27 November 2025 by Admin-Lavi Leave a Comment

This project is for Laser Security Alarm Circuit using LDR and BC547 Transistors. It uses LDR, two BC547 transistors, one diode and a buzzer. When laser light breaks an alarm rings. Circuit is cheap and very easy to build. Good for door security, box security and drawer protection. Circuit Working: Parts List: Component Value Quantity […]

Filed Under: LDR Circuits, Security and Protection, Transistor Circuits

Smart Street Light Control Circuit

Last updated on 4 November 2025 by Admin-Lavi Leave a Comment

Light ON at night and light OFF in day all automatic! All this is done with one LDR and a BC547 transistor. This Smart Street Light Control Circuit is a easy and simple way to save energy. There is no manual effort and no energy waste. Circuit Working: Parts List: Component Name Specification Quantity Resistors […]

Filed Under: LDR Circuits, LED and Lamps, Transistor Circuits

LDR Based Dark Sensor Circuit

Last updated on 2 November 2025 by Admin-Lavi Leave a Comment

This small LDR Based Dark Sensor Circuit is very smart. It can see light and dark using LDR. When there is light, everything stay quiet. When it becomes dark then LED start to glow and buzzer makes sound. No need to touch anything it works by itself. It is easy to make with low cost […]

Filed Under: LDR Circuits, LED and Lamps, Transistor Circuits

LDR Light Sensor Circuit using BC547

Last updated on 1 November 2025 by Admin-Lavi Leave a Comment

This LDR Light Sensor Circuit using BC547 works by itself. When it is dark the LED turns ON. When light comes then LED turns OFF. LDR feels the light and controls the LED. No need to press any switch. Circuit is simple and is with very low cost. It is good for small night lamp […]

Filed Under: LDR Circuits, Transistor Circuits

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