Two zener diodes are connected as shown in Fig. P4.37. The diode current in the forward direction is described by

where V_T = 0.026 and I_S = 5 × 10^−₁₅ A. The supply voltage v_S is 7.5 V. The zener voltage V_Z of each diode is 6.7 V, and the zener resistance R_Z is negligible. The forward voltage drop V_TD of each diode is 0.8 V. Determine (a) the expression for each diode voltage v_D1 and v_D2, (b) the operating diode voltages V_D1 and V_D2, and (c) the diode current I_D.

FIGURE P4.37

  

D ip=15(en/VT-1).