Response to the following :
Provide two designs of shunt regulators utilizing the 1N5235 zener diode, which is specified as follows: VZ =6.8 V and rz = 5Ω for IZ = 20 mA; at IZ = 0.25 mA (nearer the knee), rz = 750Ω .
For both designs, the supply voltage is nominally 9 V and varies by ± 1 V. For the first design, assume that the availability of supply current is not a problem, and thus operate the diode at 20 mA.
For the second design, assume that the current from the raw supply is limited, and therefore you are forced to operate the diode at 0.25 mA. For the purpose of these initial designs, assume no load.
For each design find the value of R and the line regulation.