Hello friends, I hope you are doing well. In this tutorial, we will design the timing logic for a modified sine-wave inverter and study the original CD4047B and CD4017B approach. We will also develop an equivalent microcontroller timing example so you can see exactly how the positive, zero and negative intervals are produced. This article follows our tutorials on the basics of inverter topologies , the major inverter components and the pure sine-wave inverter . A modified waveform is simpler than filtered SPWM, but its harmonic content limits the loads that should use it. Figure: The comparison shows sinusoidal and stepped waveforms over a labeled 20 ms cycle. What Is a Modified Sine Wave? A modified sine wave is a stepped bipolar waveform. During each cycle, the inverter applies a positiv ...
Hello friends, I hope you are doing well. In the previous tutorials, we studied the basics of inverter topologies and the major components of an inverter . We will now connect those ideas and study how an AVR controller can create a sine reference for a pulse-width-modulated inverter. This tutorial explains the signal chain, frequency calculations, H-bridge states, LC filter and transformer. The AVR code is an educational SPWM reference generator for an ATmega16 running at 8 MHz. It is useful for simulation and low-energy waveform testing, but it must not be connected directly to power MOSFET gates. A physical inverter needs proper high-side and low-side gate drivers, hardware dead time, current limiting, voltage feedback, thermal protection and a safe PCB layout. The original project pack ...
Hello friends, I hope you are doing well. In the previous tutorial, we studied the working principle of a relay . Today, we will connect a 12 V relay to a PIC18F4550 microcontroller through a ULN2003A driver. A relay coil needs more voltage and current than a microcontroller pin should provide. It is also an inductive load, so it produces a voltage transient when switched off. The ULN2003A solves these interface problems by providing seven low-side Darlington drivers and seven internal clamp diodes in one package. The key point is that the ULN2003A does not convert a 5 V logic signal into a 12 V output. The 12 V energy comes from a separate 12 V supply. A logic high merely turns on one internal driver, which connects the low side of the relay coil to ground. We will examine that current pa ...
Hello friends! In this tutorial, we will design an LED blinking project using the PIC16F877A microcontroller. It is a simple project, but it introduces several ideas that appear in almost every embedded system: configuring an I/O port, choosing an oscillator, building a reset circuit, calculating LED resistors, generating a time delay, compiling a program, and loading the resulting HEX file into Proteus. We will connect eight LEDs to PORTB and switch the complete port between logic low and logic high. Once this basic version works, you can change the output patterns and timing to create a running light, binary counter, or status display. The important objective is to understand why every connection and every program statement is present. Figure: The original simulation shows the PORTB LED ...
