ZM4729A-GS18

ZM4729A-GS18 is a single Zener diode, and the application field and working principle are closely related. Zener diodes are widely used in different applications. It can used in voltage regulators, overvoltage protection circuits, polarity protection circuits and clipper circuits.

Application Field of ZM4729A-GS18 Zener Diode

• Voltage Regulators
• Overvoltage Protection Circuits
• Polarity Protection Circuits
• Clipper Circuits

A voltage regulator is a device that maintains its output voltage at a constant level in spite of changes in load. Zeners are used as voltage regulators to provide a known voltage under all conditions. The Zener diode is a heavily doped diode whose reverse breakdown voltage is almost independent of its operating temperature. Hence its breakdown voltage can be precisely set in manufacturing.

In overvoltage protection circuits, the Zeners provide a control loop to prevent the unwanted rise of the output by limiting the input. The Zener diode is connected in reverse bias and a voltage in the diode is generated. When the input voltage is more than certain predetermined value, it will start conducting, and the current through the Zener diode is limited to a safe value by the resistor in series. The over-voltage protection circuit works by limiting the maximum voltage across any load.

In polarity protection circuits, Zeners are used as a bi-directional clamp that limits the voltage that can be applied across a load. The Zener will prevent the voltage from amplifying or decreasing beyond a set value and so protects the load from damage. Zener diodes are usually used as the clamps and are connected anti-parallel over the load so that the current flows through it in the reverse direction whenever it becomes more than the predetermined value.

In clipper circuits, the output is limited by the Zener diodes. They are used to clip off the positive and negative peak voltages of an AC signal and thus protects any connected equipment from damage due to over-voltages. The Zener diode conducts when the voltage exceeds the breakdown voltage and it limits the amount of current that can pass through, thus protecting the connected circuit. The Zener diode clipper works by confirming the voltage and the current which flows through the circuit.

Working Principle of ZM4729A-GS18 Zener Diode

The working principle of a Zener diode is relatively easy to understand. When a suitable voltage is applied across the diode, it is connected in reverse bias and a voltage in the diode is generated, as shown in the figure below. At this voltage, the diode is said to be in the “Zener Breakdown” region. This breakdown voltage is determined by the Zener diode\'s doping characteristics.

Below the breakdown voltage, the reverse current through the diode is virtually zero. But, when the voltage increases beyond the breakdown voltage, the current through the diode increases exponentially, as seen in the figure. The maximum current through the diode is limited by adding a resistor in series with the diode. The Zener diode can be used as a voltage regulator by providing a constant output voltage in spite of changes in the input voltage.

The Zener diode is also used to produce a stable reference voltage for powering many circuits. It provides a stable voltage output even when the input voltage varies. This makes it useful for applications such as voltage regulation and over-voltage protection. A Zener diode can be used in combination with a resistor and a capacitor to create a simple voltage regulator circuit that can keep the output voltage constant.

Zener diodes can also be used in clipper circuits to clip off the positive and negative peak voltages of an AC signal. The Zener diode conducts when the voltage reaches its breakdown voltage, and the current through the diode is limited by a resistor in series.

This description describes the application field and working principle of the ZM4729A-GS18 Zener diode in detail. As we have seen, Zener diodes are widely used in different applications due to their ability to provide a stable reference voltage and to limit the maximum voltage across any load.