A 24 V, 600 mW, Zener diode is to be used for providing a 24 V stabilized supply to a variable load. Assume that for proper Zener action, a minimum of 10 mA must flow through the Zener. If the input voltage is 32 V, what would be the value of R and the maximum load current? \n\n[Figure needs to be uploaded later]
- A. 320 $\Omega$, 10 mA
- B. 400 $\Omega$, 15 mA
- C. 400 $\Omega$, 10 mA
- D. 320 $\Omega$, 15 mA
Answer: D. 320 $\Omega$, 15 mA
Explanation: [Figure needs to be uploaded later]\n$V_z = 24~V, P_z = 600~mW, I_{zk} = 10~mA$. \n$I_{zmax} = \frac{P_{zmax}}{V_z} = \frac{600~mW}{24~V} = 25~mA$. \nWhen $I_{zmax}$ occur, no current flow through $I_L$ i.e. $R_L$ is open circuited. \n$25~mA = \frac{32 - 24}{R} \Rightarrow R = \frac{8~V}{25~mA} = 320~\Omega$. \n$I = \frac{32 - 24}{320} = 25~mA$. \nMaximum load current $I_{Lmax} = I - I_{zk} = 25~mA - 10~mA = 15~mA$.