What is the function of the negative terminal connected to a diode

In electronic circuits, diodes, as a fundamental semiconductor device, play a crucial role in various functions such as rectification, switching, voltage regulation, and signal modulation due to their unique unidirectional conductivity. Among them, the negative pole connected diode, also known as the voltage regulator diode, is a special type of diode, and its negative pole plays a particularly unique and important role in the circuit. This article will delve into the role of connecting the negative electrode of a diode to the negative electrode, analyze its working principle, application scenarios, and advantages.

1、 Construction and working principle of negative terminal connected diode

The biggest difference between a diode with a negative electrode and a regular diode is that it has a special silicon wafer structure, where two P-N junctions are connected on the silicon wafer to form a special doped region. This structure enables the negative terminal diode to conduct current at a specific reverse voltage and maintain a relatively stable voltage drop during conduction.

When the anode of the diode is connected to the low potential terminal of the power supply and the cathode is connected to the high potential terminal of the power supply, it is in a reverse bias state. Before the reverse voltage reaches the breakdown voltage, there is almost no current flowing through the diode and it is in a cut-off state. However, when the reverse voltage exceeds the breakdown voltage, a breakdown effect occurs inside the diode, producing an inverted current, that is, a negative current, at which point the diode begins to exert a stabilizing effect.

2、 The function of connecting the negative pole of a diode to the negative pole

The main function of the negative terminal of the diode in the circuit is to adjust and control the voltage of the circuit, ensuring that the circuit can maintain a stable output voltage when the load changes. Specifically, the negative terminal connected to the diode serves as the control terminal and plays the following important roles:

Voltage stabilization: When the negative terminal is connected to the diode in the reverse breakdown state, its reverse breakdown voltage is constant. By connecting a current limiting resistor in series, it can ensure that the current after breakdown does not exceed the allowable value, thus maintaining a stable breakdown state for a long time. This characteristic makes the negative terminal diode an ideal voltage regulator in circuits.

Protection circuit: In the circuit, connecting a negative diode can reduce circuit noise and electromagnetic interference, protect the circuit from voltage fluctuations and overvoltage shocks, and improve the reliability and stability of the circuit.

Signal stability: In high-power signal amplification circuits, using a negative diode can ensure signal stability, improve signal accuracy, and avoid signal distortion caused by voltage fluctuations.

3、 Application scenarios of negative terminal connected diode

The negative terminal diode has been widely used in electronic circuits due to its unique voltage stabilization performance. Here are some typical application scenarios:

Power regulator: A voltage regulator with a negative diode as its core, which can maintain the voltage in the circuit within a stable range and is suitable for various electronic devices that require stable voltage supply.

Protection circuit: Adding a negative diode to the power input or critical circuit nodes can effectively prevent voltage fluctuations and overvoltage shocks from damaging the circuit.

Signal amplification circuit: In high-power signal amplification circuits, using a negative diode can ensure the stability and accuracy of the signal, and improve the signal amplification effect.