Basic concepts Datasheets Inverters

How do Inverters work? | Designing | Configuration

Hello Engineers, I hope you all are rocking! For some people, especially beginners, it’s tricky or confusing to understand,” how do inverters work? “. Their working topology, basic concepts, and basic load and backup power calculations, etc. All these basic conceptual things come in role-playing when designing an inverter device according to desired requirements. So, I am going to write an article over how do inverters work? Basic idea/ concepts. How do inverters work? How to calculate backup time? Key points to configure design according to the output power. So, let’s begin with our topic.

What is an inverter? Working of an inverter.

An inverter is a powerful electronic device or circuitry that converts DC input power from a battery source to an equivalent stepped-up AC Output power. It takes DC input power from a battery to provide us uninterrupted AC supply at times of Camping or domestic power cut-off. The power handling capacity, backup time, output quality and output voltage of an inverter, all depends on its circuitry, design, and it’s type. Totally, there are concepts of power electronics.

Inverters also convert 12v or 24v DC voltage from a battery AND provide us stepped-up output as 220V/110V AC.SUPPLY DURING THE ELECTRICITY CUTOFF(also known as UPS).

Basically, Inverters are of 2 main types with respect to their output quality( waveform):-

1. Sine-wave Inverters:- Sinewave inverters are those inverter types whose output is sinusoidal and considered very clean. These have nearly a perfect output waveform close to the domestic AC supply. Although they are further divided into 2 types, i.e:-

*Pure sine wave (Having pure sinusoidal waveform output)

*Modified Sinewave or Modified squarewave (Having modified PWM controlled output waveform).

2. Squarewave Inverters:- Square-wave are the most common types and usually provide comparatively less efficient output with low-quality AC but still fine for normal use and even used widely. These kinds of inverters aren’t suitable for sophisticated AC devices.

Basic working and components of an inverter

How do inverter work?

How does an inverter works?


  1. INPUT STAGE:- An inverter requires 12v DC or 24V DC input with adequate current from a powerful long-run battery with sufficient amperes ratings according to the power requirements.
  2. DC TO AC CONVERSION OR OSCILLATOR STAGE:- In this stage, the dc input from the battery is converted to AC via an a-stable Oscillator circuit. An oscillator is a device or a circuit that converts unidirectional current flow from a DC source like a battery to an alternating waveform of some desired frequency according to country standards.
  3. POWER AMPLIFICATION:- Usually done by MOSFETs and power transistors.
  4. STEP UP  OR VOLTAGE STEPUP STAGE:– After the DC has been converted to AC and amplified, now the converted AC voltage needs to be stepped up to 220/110v AC for domestic use.

Block diagram for inverter and its connection and operation with AC mains

How do inverter work?

I think upper block diagram might be helpful so as to provide a conceptual vision. But the basic idea is that the AC domestic supply keeps battery changing when supply is present and at the same time powering the devices. When Power-cut occurs the change-over circuitry changes the switch from AC mains to Inverter and inverter starts to operate and power the device. Before that, the inverter was off and the only battery was charging.

Click here to see a squarewave 60watts inverter design.

Check out IC CD4047 inverter design | 150 watts

IC555 100Watts Inverter with 50.12% Duty Cycle, 55hz , Squarewave.

How to Figure out and Calculations power output/ Battery backup/ transformer?

Follow this Online Astable IC555 Calculator to calculate the IC555 timer Circuits

Available power / Power theory

  • Total INPUT POWER = OUTPUT POWER(backup)
  • OUTPUT POWER = VOLTAGE*O/P CURRENT across the device
  • Output VOLTAGE INCREASES as the CURRENT DECREASES but power remains the same supplied by the transformer.
  • Also, the Output power is dependent over MOSFETs used for each stage, Total bearable transformer power V*A and of course battery power input.

Backup Time

  • Backup time depends upon Battery ah value as,
  • Total available battery backup power(Ah*Vin) / load power requirement = backup time(in hours)


  • Output VOLTAGE INCREASES as the CURRENT DECREASES but power remains the same supplied by the transformer.
  • The Output power is dependent over MOSFETs used for each stage, Total bearable transformer power V*A and of course battery power input.

The Transformer

STEP-UP TRANSFORMER:  A step-up transformer is a stepped down transformer used in a reverse manner. This means the secondary side used as primary and primary used as secondary.

Just transformer for inverter purposes is used in a reverse manner and usually have a hight amperage like 12v 5 amp Transformer,10 amps,15, or even 25 amps, with specific VA ratings.

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Aabhishek Sharma is a Computer Science Engineer and a Digital Marketing Trainer and Consultant. Aabhishek Sharma also loves working on Electronics Projects and working with microcontrollers and Designing Home automation Gadgets.

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