Introduction

An Inverter Circuit is an electronic device that converts DC (Direct Current) power into AC (Alternating Current) power. Since batteries and solar panels produce DC power, inverters are essential for operating AC appliances during power failures.

Inverters are widely used in home UPS systems, solar power systems, emergency power backups, and industrial applications.

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Objective of the Project

• To convert DC voltage into AC voltage.
• To understand inverter working principles.
• To study switching circuits and transformers.
• To provide backup AC power during power failure.

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Working Principle

An inverter works on the principle of switching DC power alternately to create an AC waveform.

Step-by-Step Working

1. A DC source (battery) supplies power to the circuit.
2. Switching components (transistors/MOSFETs) rapidly turn ON and OFF.
3. The DC current is alternately reversed.
4. A transformer steps up the voltage.
5. AC output is obtained at the transformer output.

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Types of Inverters

• Square Wave Inverter
• Modified Sine Wave Inverter
• Pure Sine Wave Inverter

(This project demonstrates a basic square wave inverter.)

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Components Required

• Battery (12V DC)
• Transformer (12V–220V)
• Power Transistors (2N3055 / MOSFET IRFZ44)
• Resistors
• Capacitors
• Oscillator IC (IC 555 – optional)
• Heat Sink
• Connecting Wires
• Load (AC bulb)

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Circuit Diagram (Basic Inverter Circuit)

Circuit Description

Battery (+) → Switching Circuit → Transformer (12V side)
Transformer (220V side) → AC Load
Battery (-) → Common Ground

Transistors switch the DC power alternately, creating AC at transformer output.

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Inverter Circuit Using IC 555

Working

• IC 555 generates square wave pulses.
• Pulses drive power transistors.
• Transformer converts low-voltage AC to high-voltage AC.

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Arduino-Based Inverter (Optional Advanced Version)

Additional Components

• Arduino Uno
• MOSFET Driver
• MOSFETs
• Transformer

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Arduino Code for Inverter (Basic Square Wave)

int pin1 = 8;
int pin2 = 9;

void setup() {
  pinMode(pin1, OUTPUT);
  pinMode(pin2, OUTPUT);
}

void loop() {
  digitalWrite(pin1, HIGH);
  digitalWrite(pin2, LOW);
  delay(10);

  digitalWrite(pin1, LOW);
  digitalWrite(pin2, HIGH);
  delay(10);
}

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Code Explanation

• Arduino alternately switches two output pins.
• Creates square wave AC signal.
• Drives transformer via MOSFETs.
• Produces AC output.

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Advantages

• Provides backup power
• Portable power source
• Useful in remote areas
• Can work with solar systems

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Applications

• Home UPS systems
• Solar power systems
• Emergency lighting
• Industrial backup systems

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Safety Precautions

• Use proper insulation
• Avoid touching high-voltage output
• Use heat sinks for transistors
• Test with low load first

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Future Enhancements

• Pure sine wave inverter
• LCD display monitoring
• Overload protection
• IoT-based inverter monitoring

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Conclusion

The Inverter Circuit is a fundamental power electronics project that demonstrates DC to AC conversion. It plays a crucial role in modern power systems and is an excellent learning project for students studying electronics and electrical engineering.