What is a Zener Diode?

A Zener diode allows current to flow not only from its anode to its cathode but also in the reverse direction when its Zener voltage is reached. They are used as voltage references and to regulate the voltage across small circuits. Zener diode networks or arrays are devices of two or more diodes in a single surface mount package. The diodes may be isolated from each other or connected in a common anode or common cathode circuit type.

Common Zener Diode Specifications

Current Iz (max): This represents the maximum current at the rated Zener Voltage (Vz), which can range from 200μA to 200A.

Current Iz (min): This is the minimum current necessary for the diode to enter breakdown.

Forward Bias: The voltage across the diode that enables current to flow easily in one direction.

Power Rating: Indicates the maximum power the Zener diode can dissipate, calculated as the product of the diode voltage and the current flowing through it.

Reverse Bias/Zener Effect: The voltage applied across the diode in the reverse direction of forward bias, which does not produce detectable current flow. This voltage is responsible for converting AC to DC and manipulating other electronic signals.

Temperature Stability: Diodes operating around 5V exhibit the best stability.

Voltage Tolerance: Typically ±5%.

Zener/Breakdown Voltage (Vz): This is the minimum voltage required to cause a portion of the insulator to break down and become conductive. The voltage can range from 2.4V to 200V, with some exceeding 1kV, while the maximum for surface-mounted devices is 47V.

Zener Resistance (Rz): The resistance presented by the Zener diode.