What is the difference in zener diode and resistor ?

A resistor and a Zener diode serve different functions in electronic circuits. A resistor is a passive component that opposes the flow of electric current, converting electrical energy into heat. It is used to control current flow, set voltage levels, or divide voltages in a circuit. A Zener diode, on the other hand, is a specialized type of diode that allows current to flow in both directions when forward biased like a regular diode, but it also conducts in reverse bias when the voltage across it exceeds its breakdown voltage, known as the Zener voltage. This characteristic makes Zener diodes useful for voltage regulation and protection against voltage spikes.

The primary difference between a resistor and a Zener diode lies in their electrical properties and applications. A resistor always dissipates power as heat and has a linear voltage-current relationship according to Ohm’s Law. In contrast, a Zener diode is designed to operate in reverse breakdown mode when a specific reverse voltage (Zener voltage) is exceeded, maintaining a nearly constant voltage across it. Zener diodes are used primarily for voltage regulation and stabilization, whereas resistors are used for current limiting, voltage dropping, and signal conditioning.

In many applications, a resistor is typically needed in series with a Zener diode to limit the current flowing through it and to ensure proper operation. Without a series resistor, the current through the Zener diode could exceed its maximum rated current, potentially damaging the diode or causing it to operate unreliably. The value of the series resistor is chosen based on the desired current through the Zener diode, the supply voltage, and the Zener diode’s characteristics to ensure stable and safe operation within specified limits.

The main difference between a Zener diode and a normal diode lies in their breakdown characteristics. While both diodes conduct current in the forward bias direction, a Zener diode is designed to operate in reverse breakdown mode beyond its Zener voltage rating. This reverse breakdown occurs at a specific voltage level called the Zener voltage, where the Zener diode starts conducting in reverse direction and maintains a relatively constant voltage drop across it. In contrast, a regular diode typically experiences breakdown in the reverse bias region that can lead to permanent damage if exceeded, whereas a Zener diode is designed to sustain and regulate at its Zener voltage.

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