Power Failure and Resumption Alarm Circuit using 555 IC

Manikandan K J 2 Dec 2019

⚡ Power cuts can cause inconvenience, equipment damage, and even safety risks. That’s why a Power Failure and Resumption Alarm Circuit using 555 Timer IC is a simple yet powerful solution! This DIY electronics project not only alerts you when electricity goes off but also notifies you when it returns. ✅ With just a few components, you can easily build this circuit at home and enjoy peace of mind during unexpected outages.

🌟 Benefits of Power Failure and Resumption Alarm

🖥️ Protects Equipment – Prevents damage to sensitive devices like computers, servers, and medical equipment.
🛡️ Ensures Safety – Alerts you when emergency lights, alarms, or security systems lose power.
💼 Business Continuity – Helps companies minimize downtime and resume operations quickly.
🔋 Energy Awareness – Provides insights into power interruptions for better energy management.
😌 Peace of Mind – Stay worry-free knowing outages and restorations are instantly detected.

⚙️ How the Circuit Works

This circuit is designed to detect power failure and restoration in AC mains using a 555 timer IC in monostable mode.

Power Failure:
- When mains fail, transistor Q1 (BC558) is triggered.
- Stored charge in capacitor C3 powers the buzzer and Red LED (L2).
- Increasing C3 (1000µF → 2200µF or 4500µF) increases alarm duration.
Power Resumption:
- When mains return, Green LED (L1) lights up.
- A buzzer sounds for a short duration, determined by R3 and C2 values.
- Alarm automatically stops after the set time.
The circuit runs on a 9V battery with a 12V power supply.
It can also give short beeps for voltage fluctuations.
Compact enough to be installed in homes, offices, shops, or industries.

🛠️ Components Required

Resistors (¼ W):

R1 – 4.7K
R2 – 3.3K
R3 – 100K
R4 – 2.2K
R5 – 4.7K
R6 – 10K (optional)

Capacitors:

C1 – 47µF / 25V
C2 – 100µF / 25V
C3 – 1000µF / 25V
C4 – 0.01µF ceramic
C5 – 47µF / 25V

Other Components:

LEDs – L1 (Green), L2 (Red)
Diodes – D1, D2, D3 (1N4007)
DB1 – DB107 Bridge Rectifier
IC – 555 Timer
Q1 – BC558 (PNP transistor)
9V Battery
DC Buzzer
0–12V, 200mA Transformer
General-purpose PCB

Prototype of Power Failure and Resumption Alarm Circuit using 555 IC

✅ Final Thoughts

The Power Failure and Resumption Alarm Circuit using 555 Timer IC is an excellent DIY project for anyone who wants to stay informed about power status. ⚡ Whether for home, office, or industry, this circuit ensures safety, protects equipment, and provides timely alerts. With a handful of components, you can easily build it and enjoy uninterrupted confidence during outages! 🔋🔔