#76 How to Test Feedback circuit in SMPS Urdu / Hindi and how feedback circuit works

Watch this video in English Language    • #275 How to Test Feedback circuit in SMPS ...   in this video i discussed in urdu hindi what is feedback circuit in switch mode power supply smps. how to test feedback circuit in switching mode power supply. the optocoupler is connected to positive source through a current limiting resistor and the cathode of optocoupler is connected to adjustable zener regulator which provides offset voltage to the optocoupler upon getting the reference level at its pin 1 through voltage divider resistor set. so the Ripples in output high line are transferred to the pwm through optopcoupler by means of varying light in the optopcoupler due to the Ripples in Output. it causes the output transistor junction resistance to vary, this varying resistance is fed to feedback pin of pwm controller. which utilitizes it to adjust pulse width duty cycle