The top circuit, in the diagram above, is a half-wave rectifier and you can see the circuit’s effects on a sinusoidal signal. What is the bottom circuit and how would it effect a sinusoidal input?

This circuit was designed to meet a medical application’s requirement to drive a laser diode with reasonable precision and a minimum of components and footprint (the device is now in clinical trials).

In the old days every instrument or system had a power supply board with discrete, homemade regulators on it to power the system. Then IC’s like the LM7805 series of voltage regulators changed ...