This is an example of designing a PWM dimming of an LED with a simple 555 timer for an automotive application. The design can be tested live on the SystemVision website. The modulation frequency can be tuned by adapting a fixed resistor value. The different threshold for current control can be adapted by changing the fixed resistor values of the sensing bridge. The heat produced by the LEDs and the transistor is directly injected into the common heatsink, and the resulting temperature is then read by the NTC thermistor to indicate the needed status for the PWM. It is full ON-current under a threshold and then progressive PWM until a second threshold, above which total cut-off will eventually be operated. This design is fully adaptable with the most important parameters, allowing for modification by the user and their influence is directly visualized on-screen in real time.