3 Led Battery Monitor
This simple battery level indicator circuit uses a combination of BC547 (NPN) and BC557 (PNP) transistors along with a Zener diode (BZX79C12) to monitor voltage levels and display the battery status through three LEDs.
- Green LED indicates full charge or normal operating voltage.
- Yellow LED signals a medium charge or partially discharged state.
- Red LED warns of a low battery condition, suggesting that recharging is required.
Thanks to its low component count and low power consumption, this circuit is ideal for portable devices, battery-powered projects, or as an educational tool for understanding transistor-based voltage monitoring.
