Chapter 2, Problem 2.91IP

Nonlinear Device Characteristics
The circuit in Figure P2-91 is a parallel combination of a $75\text{-Ω}$ linear resistor and a varistor whose $i-v$ characteristic is $i_{\text{V}}=2.6\times {10}^{-5}{v}^3.$ For a small voltage, the varistor current is quite small compared to the resistor current. For large voltages, the varistor dominates because its current increases more rapidly with voltage.

1. Plot the $i-v$ characteristic of the parallel combination.
2. State whether the parallel combination is linear or non-linear, active or passive, and bilateral or nonbilateral.
3. Find the range of voltages over which the resistor current is at least 10 times as large as the varistor current.
4. Find the range of voltages over which the varistor current is at least 10 times as large as the resistor current.