In the circuit shown, a 5 V Zener diode regulates the voltage across load \(R_0\). The input DC varies from 6 V to 8 V. The series resistor is \(R_S = 6\,\Omega\). The Zener diode has a maximum power rating of 2.5 W. Assuming an ideal Zener diode, the minimum value of \(R_0\) is \(\underline{\hspace{2cm}}\) \(\Omega\).
