The circuit inside the shaded area in Figure. 1 is a constant current source for a limited...

The circuit inside the shaded area in Figure. 1 is a constant current source for a limited range of values of RL.

a) Find the value of iL for RL = 4 kΩ.

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b) Find the maximum value for RL for which iL will have the value in (a).

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c) Assume that RL = 16 kΩ. Explain the operation of the circuit. You can assume that in=ip ≈ 0 under all operating conditions.

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d) Sketch iL versus RL for 0 ≤ RL ≤ 16 kΩ.

Figure. 1