Re: regulators
maxwell_28,
Zeners are used in two ways.
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The simplest is to use the Zener directly as a shunt regulator. Zeners have the property that the voltage is relatively independent of the current through the Zener.
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The Zener can also be used as the reference voltage for an active regulator. The error voltage, which is the dfference between the reference voltage and the output voltage, is used to regulate the output through a pass transistor. In a switching regulator, the error voltage is used to control the duration during which the switching element is turned on.
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Other devices, such as voltage reference ICs are often used in place of Zeners, because of their superior regulation and lower temperature coefficients.
Regards,
Kral