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pc2-brazil

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## Homework Statement

The attached figure is an illustration of a crude Zener-diode regulator circuit.

a) Using incremental analysis, estimate from the graph an analytical expression for v

_{0}in terms of V and Δv.

b) Calculate the amount of DC and the amount of AC in the output voltage using the Zener-diode characteristic to find model values.

## Homework Equations

## The Attempt at a Solution

First I assume that the current i

_{Z}in the circuit goes in the direction of the diode's arrow. v

_{Z}, the voltage across the diode's terminals, is minus v

_{0}. Applying KVL to the circuit in the attached figure, I find that [itex]V+\Delta v = v_0 - i_ZR_1 = -v_Z - i_ZR_1[/itex].

To find an expression for [itex]v_Z[/itex], I first have to find the operating point values [itex]V_Z[/itex] and [itex]I_Z[/itex] in terms of V, considering the case when Δv = 0 (that is, ignoring the small signal). This gives: V = -I

_{Z}R

_{1}- V

_{Z}, or V

_{Z}= -I

_{Z}R - V. So I think I should do a graphical analysis, plotting the line v

_{Z}= -i

_{Z}R

_{1}- V at the given graph to estimate the intersection point V

_{Z}, I

_{Z}.

But the graph doesn't seem to give enough details for being able to find an intersection point.

Any hints on how to proceed?

Thank you in advance.

#### Attachments

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