To get precise voltage to a circuit, the simplest and easy way is to use a Zener diode.It uses the reverse breakdown voltage characteristics to maintain a fixed voltage across it Zener diode ZD is ...

Determine the range of values of Vi that will maintain the Zener diode of the figure above in the “on” state. To solve for Vi(max), we use the formula But, since IR(max) is not yet known, we have to ...