Current Sources and Voltage References

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Characteristics of the zener diode

rent and voltage values allows the circuit board designer to calculate the approximate

zener resistance/impedance anywhere along the reverse V-I curve, between I

ZK

and

I

ZM

. Typically, the lower the zener’s impedance, the better the regulation will be. It is

usually measured at the factory during a computer-controlled test procedure, using

either a 60-Hz or 1-KHz AC signal, and the result must be within predefined levels.

This signal is usually 10% in AC

rms

of the DC current value, and equates to:

One can determine small voltage changes (

∆

V

Z

), from the nominal zener voltage (V

Z

),

with small changes ...