The SG3524 PWM controller is often missing from the default Proteus component library. To simulate it, you must either download a third-party library or use a compatible alternative like the UC3525 or SG3525, which share similar functions and pin configurations. Download Sources for SG3524 Proteus Library
If you cannot find a ready-made .LIB file, do not panic. You can import a raw SPICE model from Texas Instruments or STMicroelectronics. sg3524 proteus library download
Cause: The SG3524 model has floating pins or missing power connections. Fix: The SG3524 PWM controller is often missing from
LIBRARY folder.