Introduction:
A simple inverter circuit is an essential electronic device that converts low-voltage DC (direct current) into high-voltage AC (alternating current). This basic inverter utilizes two 2N3055 NPN power transistors, resistors, and a step-up transformer. Powered by a 12V DC source, it generates a 220V AC output suitable for powering small appliances.
The transistors switch the current alternately through the transformer’s primary winding, creating a pulsating current that induces a stepped-up voltage in the secondary winding. Resistors regulate the transistor base currents, ensuring proper operation. While simple in design, this inverter produces a square wave output, which is less ideal for sensitive devices but adequate for basic applications. This straightforward circuit demonstrates fundamental inverter principles, making it an excellent starting point for beginners in electronics.
Component Requried:
| S.no | Component | Value | Qty. |
|---|---|---|---|
| 1. | Transistor | 2N3055 | 1 |
| 2. | Resistor | 220Ω 1W | 2 |
| 3. | Transformer | 12-0-12 | - |
| 4. | Battery | 12V | - |
2N3055 Pinout:
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- Pin 1 (B): Base - This is the control terminal that regulates the current flow between the collector and emitter.
- Pin 2 (E): Emitter - This is the terminal through which current exits the transistor.
- Collector (C): The tab of the metal casing serves as the collector, which is the input for the current to be amplified.
Circuit Diagram:
This simple inverter circuit uses two 2N3055 NPN power transistors, resistors, a transformer, and a 12V battery to convert DC to AC. The circuit operates by alternating current flow through the primary winding of the transformer using the two transistors, which act as electronic switches. The 220Ω resistors control the base current of the transistors, ensuring proper switching.
When one transistor is active, it conducts current through one half of the transformer’s primary winding. The other transistor then switches on, driving current through the other half, creating an alternating current. The transformer steps up the 12V input to 220V AC at the output.
This inverter produces a square wave AC output, making it suitable for low-power applications like lighting or basic appliances. However, it’s not ideal for sensitive electronics, as it lacks waveform smoothing for producing a pure sine wave.
Applications:
- Emergency Lighting Systems
- Portable Power for Camping or Remote Areas
- Basic Home Appliances (e.g., Fans, Incandescent Bulbs)
- Educational and Training Projects in Electronics