Simple 12v to 220v Inverter Circuit (DC to AC) Without using any IC Astable Multivibrator

Simple 12v to 220v Inverter Circuit (DC to AC)  Without using any IC

Inverter Circuit Diagram

Simple 12v to 220v Inverter Circuit (DC to AC)  Without using any IC Astable Multivibrator  electrobuff.blogspot.com

Hi all, and welcome. In today's blog I'll show you a simple inverter idea without using any IC, with good power output. It's built around a classic relaxation oscillator using two power transistors.

It is a classic two BJT transistor Astable multivibrator Circuit.

Overview

An astable multivibrator is a type of oscillator circuit that generates a continuous square wave output without the need for an external triggering signal. It is often implemented using two bipolar junction transistors (BJTs) in a configuration known as a BJT astable multivibrator. The circuit relies on the switching behavior of the transistors to create a repetitive oscillation. 

Here's how a basic two-BJT astable multivibrator works:

Components:
Two BJTs (Transistor Q1 and Q2): NPN transistors are commonly used.
Resistors (R1, R2, and RE): These resistors determine the biasing and timing in the circuit.
Capacitors (C1 and C2): These capacitors play a crucial role in determining the frequency of the oscillation.
Power Supply (Vcc): Provides the necessary voltage for the circuit.

Operation:

Initial State:
Assume one transistor, let's say Q1, is initially in the ON state (saturated), and the other transistor, Q2, is in the OFF state (cut-off).
The capacitor C1 charges through resistor R1 and forward-biased transistor Q1.

Charging Phase:
As capacitor C1 charges, the voltage across it increases.
Once the voltage across C1 reaches a threshold (determined by the base-emitter voltage of Q2), Q2 starts turning on.

Switching State (Transition):
As Q2 turns on, it pulls the collector voltage of Q1 low, forcing Q1 into the OFF state.
Simultaneously, capacitor C2 starts charging through resistor R2 and forward-biased transistor Q2.

Discharging Phase:
With Q1 off, C1 begins to discharge through resistor RE (emitter resistor) and the base-emitter junction of Q2.
As C2 charges, its voltage reaches a threshold, causing Q1 to start turning on.

Repeat:
The cycle then repeats, with the transistors alternately switching states in response to the charging and discharging of capacitors C1 and C2.
This continuous switching between the two states generates a square wave output at the collector terminals of both transistors.

Frequency Determination:
The frequency of oscillation is primarily determined by the values of resistors R1, R2, RE, and capacitors C1 and C2.
The formula for the frequency (f) is approximately given by: 

Frequency = 0.693 / ((R1 + 2*R2) * C1)

Output Waveform:
The circuit produces a square wave output with a duty cycle close to 50%, making it suitable for applications like clock generators and pulse generators.

In summary, the two-BJT astable multivibrator circuit utilizes the charging and discharging of capacitors through transistors to create a continuous oscillation, generating a square wave output. The timing components (resistors and capacitors) control the frequency of the oscillation.

Watch my YouTube Video Tutorail

https://youtu.be/atDxvOZmoiw?si=DpPZHkjr1WtOOL9B

Simple 12v to 220v Inverter Circuit (DC to AC)  Without using any IC Astable Multivibrator  electrobuff.blogspot.com

Simple 12v to 220v Inverter Circuit (DC to AC)  Without using any IC pcb Astable Multivibrator  electrobuff.blogspot.com

Simple 12v to 220v Inverter Circuit (DC to AC)  Without using any IC pcb Astable Multivibrator  electrobuff.blogspot.com