Tsk DC to DC sine wave inverter

Added: 2026-05-10

[00:00:02]In this video, we will learn how to convert an SG3525based square wave inverter into a pure sinewave inverter circuit. This circuit works with 12vt battery input and gives 220 volt alternating current sine wave output. The complete circuit is divided into three main sections. The square wave generator section, the SPWM pulse shaping section and the power inverter section. First we will understand the SG3525 square wave generator section. In the left side of the circuit we can see the SG3525 controller chip. This chip is mainly used for inverter and power supply designs. Inside this chip there is an internal oscillator which generates two opposite square wave signals. These signals come out alternately from the two output pins. So when one output is high, the other output becomes low. The frequency of these square waves is controlled by the resistor and capacitor network connected to the timing pins. In this design, the values are selected so that the output frequency becomes 50 Hz which is required for household alternating current. Now these square waves cannot directly produce a sine wave. So we must convert them into smooth rising and falling waveforms. For this purpose, resistor and capacitor integrator networks are connected to each output of the SG3525 chip. These networks slowly charge and discharge the capacitors which changes the sharp square wave edges into curved waveforms. As a result, we get two low frequency signshaped signals which are opposite in phase. Next comes the pulse shaping section. The sine wave signals from the integrator networks are fed into two separate 555 timer circuits.

[00:01:41]Each 555 timer is configured in pulse width modulation mode. The sine wave is applied to the control pin of the 555 timer. Inside the 555 timer, a high frequency triangular waveform is compared with the sine wave input. When the sine wave voltage rises, the pulse width becomes wider. When the sine wave voltage falls, the pulse width becomes narrower. In this way, the output becomes a pulse width modulated waveform that accurately follows the sine wave shape. Two identical pulse width modulation signals are generated, one for each half cycle of the alternating current waveform. These signals are perfectly synchronized and opposite in timing which is very important for pushpull inverter operation. Now we come to the power inverter section. The pulse width modulated signals from the 555 timers are fed into the gates of power metal oxide semiconductor field effect transistors. Here IRF 3205 power devices are used. These transistors act as high-speed electronic switches. When the pulse width modulated signal goes high, the transistor turns on and allows current from the battery to flow through one half of the transformer primary winding. When the signal goes low, the transistor turns off. The opposite set of transistors then turns on during the next half cycle. Because the switching follows a pulse width modulated sign pattern, the current flowing through the transformer primary also follows a sine wave envelope. The transformer then steps up the 12vt alternating waveform to around 220 volts alternating current at the secondary side. Fast recovery diodes are connected across the transformer winding to protect the transistors from voltage spikes generated due to inductive switching.

[00:03:23]These diodes safely clamp the reverse voltage and improve the reliability of the circuit. At the output side, a high voltage capacitor is connected. This capacitor filters the pulse waveform and smooths it further converting the stepped waveform into a clean sine wave alternating current suitable for household loads. So friends, this is how the SG3525based sine wave inverter circuit works from start to end. If you understand the signal flow step by step, then this circuit becomes very easy to build and troubleshoot. With proper transformer rating, good heat sinks for the power transistors and a healthy battery. This inverter can give reliable pure sine wave alternating current output for many applications. If you like this explanation and find it useful, then please support the channel by liking the video, sharing it with your friends, and subscribing for more practical electronics projects. Thank you for watching. Take care and see you in the next video.

[00:04:17]>> PSerisank me. Where do I begin? A fear of what's uncertain.

[00:04:30]The unknown feels like home. With every step I'm finding, a place I've never known. Let's go where no one there's ever been. A world I've seen needless skin. The skies will break the chain.

[00:04:49]Atted them all. Rise like ting.