COURSES TAUGHT BY PROF. VALDENILTON: Basic Electronics Course Level 1 and 2 Online (100% in VIDEO) https://go.hotmart.com/S90922297H?dp=1 Digital LCD/LED TV Repair Course (100% in PDF) https://technologycursos.wixsite.com/... Transformer Winding Course (100% in PDF) https://hotm.art/Curso-de-enrolamento... COURSES TAUGHT BY OTHER TEACHERS: Basic Electronics Course (with a focus on repair) https://hotm.art/Curso-de-eletronica-... Basic Electronics Course (with a general focus) https://hotm.art/Curso-de-eletronica-... Cell Phone Repair Course (version 5.0) https://hotm.art/Conserto-de-celular-top Cell Phone Repair Course Notebook Motherboard https://hotm.art/Conserto-de-placa-ma... Voltage Inverter Manufacturing and Repair Course https://hotm.art/Aprenda-a-fazer-inve... Photovoltaic Solar Energy Course https://hotm.art/Curso-energia-solar-... Complete Digital Marketing Course (from scratch) https://hotm.art/Curso-de-Marketing-D... Introduction: The fusistor is a fundamental device for modern circuits, especially when dealing with switching power supplies. In this video, you will learn why you should not exchange a fusistor for a resistor. Definition: What is a fusistor? The fusistor is simply a resistor, which can be a metal film resistor, a carbon film resistor or a wire resistor that breaks when the temperature rises. Area of ​​application: The fusistor is widely used to generate a reference voltage for the PWM oscillator IC by monitoring the current circulating in the primary coil. Operating Principle: The PWM oscillator IC of the switched-mode power supply needs to keep the current that flows stable both in the primary coil of the chopper transformer and in the channel of the primary coil's switching transistor, which is usually an N-channel MOSFET. When the transistor is triggered by the gate through the PWM pulse, it goes into saturation, allowing a current to flow through the primary coil, creating a magnetic field in it. The current now promoted by the transistor flows through the fusistor connected directly to its Source terminal. When the current passes through the fusistor, a voltage drop is created between its terminals, which is sent back to the oscillator IC, so that it can compare internally and decide whether the current should be adjusted or not. If the current has increased, the PWM oscillator IC decreases the saturation time of the switching MOSFET. Otherwise, the PWM IC increases the saturation time of the switching MOSFET. Conclusion: The fusistor works as a resistor when the operating current is within the limit established by the manufacturer, causing a voltage drop between its terminals relative to this amount of current. If the current rises to dangerous levels, the fusitor breaks, interrupting the damaging current to protect the rest of the circuit. Technologies: The fusitor can be found in two technologies: THT, which generates PTH components, and SMT, which generates SMD components. In THT technology, it has terminals to be soldered to the PCB, and in SMT technology, it has joints to be soldered to the PCB. How to test the fusitor: The fusitor should be tested with a digital multimeter on the lowest resistance scale (usually 200 Ohms). How to replace the SMD fusitor: The SMD fusitor should be replaced with a hot air station, soldering station, or with a soldering iron along with bismuth solder. I hope that by the end of this video you will be able to replace a fusitor safely, thus avoiding causing damage to other parts of the circuit. SHARE THIS VIDEO WITH YOUR FRIENDS: • Watch This Class Before Replacing a... SUBSCRIBE TO OUR CHANNEL BY CLICKING THE LINK BELOW: / @technologycursosoficial Hello, I'm Prof. Valdenilton, Technical Coordinator of the Electronics courses taught by Technology Cursos. I love transforming people's lives through teaching. My goal is to teach people like you to repair the electronic equipment they love, helping in every way possible. INFORMATION: Our Website: https://technologycursos.wix.com/tech... Business Contact: [email protected] Whatsapp Center: (82) 9 8706-9200