PWMcontrolNPN

This circuit illustrates the basic operation of a DC-DC step down buck circuit. The diode and transistor elements are modeled using ON/OFF resistances. These elements help focus attention on other salient variables in circuit: duty cycle, L, C, parasitic resistances, and load current. The circuit provides a great way to understand some of the behaviors of this very important topology. Run the simulation. The circuit is configured to provide 5V. 1. Adjust the value of the capacitor C1. What is the affect on the output voltage ripple? 2. Slowly adjust the R_load resistor to change the load current. Does the output always remain at 5V? Observe the inductor current carefully 3. Slowly adjust the value of the inductor. What is the effect? 4. How does the capacitors ESR (Equivalent Series Resistors) impact the output? This parasitic resistor can be quite significant in the real world.