Diodes - Zener - Single

The 1N5367AE3/TR13 is an example of a Zener diode, a type of diode designed to allow electrical current to flow in one direction and cut off when the voltage across the diode exceeds the breakdown voltage. The 1N5367AE3/TR13 is a single diode designed for applications such as voltage reference, voltage clamping and over-voltage protection. This diode is usually used on circuits with voltages up to 1000V, although higher voltage models are available.

Application Field

Zener diodes are used in any situation where a predictable maximum voltage must be maintained across a circuit. In a basic voltage regulator setup, the diode is placed in parallel with a resistor connected to the DC power supply. A capacitor is also connected in parallel with the Zener diode to act as a filter. As the voltage approaches the breakdown voltage of the diode, the current through the diode increases sharply, thus keeping the voltage across the diode stable.

Zener diodes are also used as voltage references in analog circuits. Because the diode will maintain a constant voltage across it when a current is passed through it, the voltage can be used as a reference voltage to set the output of an amplifier or other device. In this situation, the resistor and capacitor must be connected in series with the diode, instead of in parallel. This prevents too much current from being drawn from the device\'s power source.

Zener diodes are commonly used in voltage clamping applications. When excess voltage is detected, the diode will clamp the voltage and protect the circuit from damage. Additionally, some diode designs allow for dynamic clamping, meaning that the diodes will react to increases in voltage quickly and reduce them before damage to the circuit occurs.

Working Principle

A Zener diode works on the principle of avalanche breakdown, which occurs when the voltage across a semiconductor increases to the point that electrons can easily cross the barrier and cause an electrical breakdown. In a Zener diode, the breakdown voltage can be adjusted by changing the amount of doping placed on the diode. This is what allows the diode to have a predictable breakdown voltage.

When the voltage across the diode is below the breakdown voltage, the diode acts like an open circuit and no current will flow through it. When the voltage is above the breakdown voltage, the electrons will easily cross the barrier, and a large current will flow through the diode. This current will drop off exponentially as the voltage increases and will remain stable when the voltage reaches its breakdown voltage.

The current through the diode can also be changed by changing the resistor connected to it. The resistor controls the amount of current that the diode will allow to pass through it and will have an effect on the voltage drop across the diode. This can be used to maintain a specific voltage across the diode, even when the load current is changing.