• Skip to main content
  • Skip to primary sidebar

Homemade Circuit Projects

Need circuit help? Post them in the comments! I've answered over 50,000!

Blog | Categories | About | Contact | Calculators-online
You are here: Home / Oscillator Circuits / Transistor based 3 Phase Sine Wave Generator Circuit
3phasegeneartorUsingTransistors

Transistor based 3 Phase Sine Wave Generator Circuit

Last Updated on January 8, 2024 by Swagatam 76 Comments

In this post I have explained a very simple 3-phase sine wave generator circuit, using only three bipolar transistors and a few passive components for initiating the desired three phase output.

Table of Contents
  • How it Works
  • Push Pull Cycle
  • Circuit Diagram

How it Works

Referring to the 3 phase sine wave generator circuit we can see three identical transistor stages configured in a cross coupled manner, having equivalent RC timing constants across their bases.

The 10k resistor and the 1u capacitor essentially become responsible of providing the required delay effect for generating the intended 3 phase signals with 120 degree phase shift.

When power is switched ON, the stages may seem to undergo a locked sequence, however since all the capacitors cannot have a precisely same value, the one which has a shade lower value than the other charges up first, triggering a sequential conduction across the transistor.

Let's assume that due to inconsistency in values, the middle transistor base capacitor gets charged first, this enables the middle transistor to conduct first which in turn grounds the base of the extreme right transistor preventing it from conducting for that instantaneous moment, but in the meantime the base capacitor of the left or the right transistor also gets charged in tandem which forces the middle transistor to switch OFF and release the right transistor conduction.

Push Pull Cycle

The above mutual push and pull procedure induces and settles into a continuous sequential train of conduction across the transistors causing the intended three phase signal pattern to appear across the collectors of the transistors. Owing to the gradual charge and discharge pattern of the caapcitrs, the resultant signal shape is a pure sine wave.

The 2K2 resistor shown in yellow strangely becomes crucial in initiating the 3 phase signal generation sequence, without which the circuit seems to stall abruptly.

As mentioned before the degree of phase may be altered by changing the RC values across the bases of the transistors, here it's configured to produce a 120 degree phase shift.

Circuit Diagram

warning message: electricity is dangerous, proceed with caution

Oscilloscope trace, 3 phase waveform

Video Illustration

Since my scope was not equipped to measure 3 phase signal, I could only manage to check a single channel in the video.

You'll also like:

  • 1.  IC 4047 Astable, Monostable Circuits
  • 2.  9 Simple Sine Wave Generator Circuits Explored
  • 3.  5 Best IC 555 Oscillator Circuits Explored
  • 4.  Sine Wave Inverter using Bubba Oscillator Circuit
  • 5.  How Blocking Oscillator Works
  • 6.  Transistor Multivibrator Circuits [Astable, Bistable, Monostable]

Filed Under: Oscillator Circuits Tagged With: Based, Generator, Phase, Sine, Transistor, Wave

About Swagatam

I am an electronics engineer and doing practical hands-on work from more than 15 years now. Building real circuits, testing them and also making PCB layouts by myself. I really love doing all these things like inventing something new, designing electronics and also helping other people like hobby guys who want to make their own cool circuits at home.

And that is the main reason why I started this website homemade-circuits.com, to share different types of circuit ideas..

If you are having any kind of doubt or question related to circuits then just write down your question in the comment box below, I am like always checking, so I guarantee I will reply you for sure!

Previous Post: « Motorcycle Voltage Regulator Circuits
Next Post: Remote Controlled Night Lamp Circuit »
Subscribe
Notify of
guest
guest
76 Comments
Inline Feedbacks
View all comments

Primary Sidebar

circuit simulator image

Subscribe to get New Circuits in your Email

Categories

  • Arduino Projects (90)
  • Audio and Amplifier Projects (132)
  • Automation Projects (17)
  • Automobile Electronics (101)
  • Battery Charger Circuits (84)
  • Datasheets and Components (105)
  • Electronics Theory (140)
  • Free Energy (37)
  • Games and Sports Projects (11)
  • Grid and 3-Phase (19)
  • Health related Projects (25)
  • Home Electrical Circuits (12)
  • Indicator Circuits (15)
  • Inverter Circuits (89)
  • Lamps and Lights (142)
  • Meters and Testers (71)
  • Mini Projects (46)
  • Motor Controller (64)
  • Oscillator Circuits (28)
  • Pets and Pests (15)
  • Power Supply Circuits (89)
  • Remote Control Circuits (50)
  • Security and Alarm (64)
  • Sensors and Detectors (103)
  • SMPS and Converters (29)
  • Solar Controller Circuits (60)
  • Temperature Controllers (42)
  • Timer and Delay Relay (49)
  • Transmitter Circuits (29)
  • Voltage Control and Protection (38)
  • Water Controller (36)

Other Links

  • Privacy Policy
  • Cookie Policy
  • Disclaimer
  • Copyright
  • Videos
  • Sitemap

People also Search

555 Circuits | 741 Circuits | LM324 Circuits | LM338 Circuits | 4017 Circuits | Ultrasonic Projects | SMPS Projects | Christmas Projects | MOSFETs | Radio Circuits | Laser Circuits | PIR Projects |

Social Profiles

  • Twitter
  • YouTube
  • Instagram
  • Pinterest
  • My Facebook-Page
  • Quora
  • Stack Exchange
  • Linkedin
  • Recent Comments

    • Swagatam on How to Convert a Low Power Inverter to a High Power Inverter
    • Swagatam on Simple Buck Converter Circuits using Transistors
    • NGANG on How to Convert a Low Power Inverter to a High Power Inverter
    • Swagatam on Make this 7 Segment Digital Clock with Beep Alert Circuit
    • Swagatam on Make this 7 Segment Digital Clock with Beep Alert Circuit

    © 2025 · Swagatam Innovations