12V Mini Inverter Circuit Using 3525 IC

The 12V CFL emergency light circuit using SG3525 IC is a simple DIY mini inverter 🔋. It can power CFL and LED bulbs up to 32W 💡; therefore, it is an excellent choice for emergency lighting during power cuts. ⚡ Furthermore, this SG3525 mini inverter circuit provides a simple yet dependable solution. In addition, it can drive regular AC CFL bulbs or LED bulbs up to 32W 💡 without difficulty. With minor modifications, such as upgrading the transformer, you can even use higher wattage bulbs. As a result, this circuit is both flexible and practical for a wide range of emergency power needs.

Circuit Diagram

⚙️ How the 12V Mini Inverter Circuit Works

This project is based on the SG3525 IC 🔲, a PWM (Pulse Width Modulator) used in many inverters and SMPS designs. Here’s how it works:

1️⃣ SG3525 IC generates PWM signals.
2️⃣ These signals drive two MOSFETs (Q1 & Q2) 🔌.
3️⃣ The MOSFETs power a push-pull step-up transformer 🔄, which converts 12V DC ➝ AC.
4️⃣ A bridge rectifier (D1–D4) 🔲 then converts the AC back to DC to power the bulb.
5️⃣ Fast switching MOSFETs ensure minimal power loss and smooth operation.

👉 Result: A compact and efficient mini inverter circuit for emergency lighting! 🌙

📊 Pinout of SG3525 IC

Key connections of the SG3525 IC:

• 📍 Pins 11 & 14 → Drive MOSFETs
• 📍 Pin 5 (CT) → Timing capacitor
• 📍 Pin 6 (RT) → Timing resistor
• 📍 Pin 15 (Vcc) → Supply voltage
• 📍 Pin 13 (Shutdown) → Protection input

🛠 Parts Required

Resistors (¼ Watt)

• R1 – 4.7K
• R2 – 18K
• R3 – 4.7K
• R4 – 22Ω
• R5 – 22Ω
• R6 – 10K
• R7 – 10K

Capacitors

• C1 – 0.001µF (102)
• C2 – 100µF / 25V
• C3 – 4.7µF / 25V
• C4 – 0.001µF (102) 1kV

Other Parts

• U1 – SG3525 IC
• L1 – Choke (100µH) ⚡
• T1 – Ferrite Transformer (EE28 core) 🔄
• MOSFETs – IRF540 / IRFZ44 / P55NF06
• Diodes – BA159 × 4 (Bridge Rectifier) 🔲
• Fuse – 1A 🔥 Protection
• Battery – 12V / Lithium Ferrous or UPS Battery 🔋

💡 For longer backup, use a 12V battery with higher Ah rating.

📌 Applications

✔️ Power CFL bulbs up to 32W 💡
✔️ Run LED bulbs (with driver circuit)
✔️ Charge mobiles & tablets 📱
✔️ Use as a home emergency light 🔦

❓ Frequently Asked Questions (FAQ)

👉 Yes, you can use any 12V battery, including UPS batteries, lead-acid, or lithium. Higher Ah (ampere-hour) batteries will give you longer backup time.

 

💡 What is the maximum bulb wattage supported?

👉 The circuit has been tested up to 32W CFL bulbs. However, you can use higher watt bulbs or LED bulbs by upgrading the transformer and MOSFETs.

 

⚡ Can this inverter circuit charge mobile phones and tablets?

👉 Yes ✅, the circuit provides a stable output that can be used to charge mobiles, tablets, and small gadgets.

 

🔧 Does this circuit include a battery charging section?

👉 No 🚫. The circuit only works as an inverter. You need a separate battery charger to recharge the 12V battery.

 

🛠 Which MOSFETs are best for this SG3525 inverter circuit?

👉 Commonly used MOSFETs include IRF540, IRFZ44, and P55NF06. They handle the switching efficiently and minimize power loss.

 

🔄 Can I replace the CFL bulb with LED bulbs?

👉 Yes, you can use company-made LED bulbs up to 32W. LEDs are more efficient and will give longer backup time compared to CFLs.

⚠️ Important Notes

• 🚫 This circuit does not include a charging section.
• ✅ Tested up to 32W CFL bulb without heatsink.
• 🔋 Works with any 12V battery (higher Ah = longer backup).
• 🔧 Can be modified to handle higher wattage bulbs.

✅ Pro Tip: If you’re using this for home backup, combine it with a solar charging system 🌞 for a complete off-grid emergency light setup.

🎯 Conclusion

The 12V CFL emergency light circuit using SG3525 IC is a DIY mini inverter that’s easy to build, cost-effective, and highly reliable ⚡. With a simple 12V battery 🔋, you can power CFLs, LEDs, and even charge gadgets during power cuts 🌙.

Perfect for homes, shops, and small backup systems ✅.