DIY 12V Battery Status Indicator | 555 Timer Circuit | Low Battery Warning LED

#555timer #batteryindicator #LEDcircuit #electronics #circuit
In this video, I'll show you how to build a Flashing LED Battery Low Indicator using a NE555 timer IC and two BC547 transistors. The circuit gives you two clear visual signals:

✅ Green LED flashing continuously → Battery is healthy
🔴 Red LED glowing solid → Battery voltage is low — charge it now!

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⚙️ HOW THE CIRCUIT WORKS
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The circuit is split into two smart stages:

Stage 1 — Voltage Sensing:
Two BC547 NPN transistors (Q1 & Q2) and a 47kΩ preset potentiometer (RV2) continuously watch the battery voltage. You set the low-voltage threshold by adjusting the pot. When the voltage drops below that point, the red LED (D2) turns on solid.

Stage 2 — 555 Astable Oscillator:
The NE555 timer is wired in astable mode using R1 (22kΩ), R2 (200kΩ), and C1 (1µF). This makes the green LED (D1) flash at a steady rate during normal conditions.

The Smart Link Between Both Stages:
The 555 timer's Reset pin (pin 4) is connected through the transistor stage. While the battery is healthy, the reset pin stays HIGH and the green LED flashes. The moment the battery goes low, Q1 conducts, pulls the reset pin LOW, the 555 stops oscillating, and the green LED goes completely dark — leaving only the solid red warning light.

Two clear states. Zero confusion.

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🔧 COMPONENTS YOU NEED
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• NE555 Timer IC — U1
• BC547 NPN Transistor × 2 — Q1, Q2
• Resistors: 200kΩ, 33kΩ × 2, 22kΩ, 2.2kΩ, 1kΩ
• 47kΩ Preset Potentiometer — RV2 (threshold adjust)
• Capacitors: 1µF, 0.01µF
• Green LED × 1 (normal indicator)
• Red LED × 1 (low battery warning)
• 12V DC power supply / battery

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💡 PERFECT FOR
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✔ Solar panel battery systems
✔ Electric fence energisers
✔ 12V lead-acid battery projects
✔ Off-grid power setups
✔ Inverter battery monitoring

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Видео DIY 12V Battery Status Indicator | 555 Timer Circuit | Low Battery Warning LED канала KS Electro