Last Updated on October 22, 2023 by Kevin Chen
Image of how diodes generate noise-Wikipedia
What comes into your mind when you hear the term ‘noise’? In the world of electronics, noise has nothing to do with the audio. Instead, it is all about the unwanted electric current that is generated in a device. We can define diode noise as a random variation of the electric current when a diode is connected in a forward bias state. The variation is usually caused by various factors and conditions, some of which are internal meaning that they are caused by the diode itself while in some cases external forces tend to generate the diode noise.
Diode noise is a major issue that should be taken seriously. It tends to affect the overall operation of the diode. Since diodes are designed to ensure that electric current or signal moves in one direction, the noise may cause some form o interference to this functionality. The direction of the signal flow may be affected leading to the leakage of electric current.
Keep reading as we discuss in detail what diode noise is and the implications that it has in electric circuits. We will also discuss ways of how to minimize diode noise.
What is Zener diode noise?
One of the commonly discussed topics in relation to the diode noise is the Zener diode noise. This is just like any other diode noise only that this one focuses on a specific type of diode; Zener diode.
If you are using a Zener diode type, you may be wondering why it seems to be noisy. This is quite a common issue especially when they are used in audio applications. The impact of the Zener diode noise is also quite clear in any other sensitive application.
The Zener noise is usually due to the Zener breakdown. This happens when there is high movement of the electrons from the p-type region to the n-type region of the diode. This breakdown ends up creating a field ionization effect. Keep in mind that Zener breakdown is slightly different from the Avalanche breakdown in diodes.
Zener diode is classified into three main categories. These are the Shot noise, Flicker noise, and thermal noise.
Shot noise is generated by the instantaneous arrival of the electrons at the junction of the diode. This noise is determined by the voltage supplied to the circuit. Flicker noise is another type of Zener diode noise. It is generated by the low frequency of various components that make up the diode. Usually, this type of noise does not have a significant impact on the circuit. Thermal noise is usually caused by the variation of temperature in the diode. Drastic temperature changes have a direct impact on the movement of electrons in the semiconductor. Such movements end up affecting the overall behavior of the circuit. This implies that thermal noise also deserves special and immediate attention.
Avalanche noise is another common cause of diode noise. This noise is generated when the voltage in the diode circuits exceeds the operating voltage of the diode. The electrons will be instantly triggered and, in a process, known as avalanche breakdown.
Diode noise can also be due to the normal combination process of the holes and electrons at the junction. The level of combination may vary from one cycle to another and this variance will ultimately lead to the generation of noise.
Take note that most of the causes of the Zener diode noise also affect other diodes.
Measures to reduce diode noise in circuits
At this point, you know the possible cause of diode noise. It will be easier to come up with measures and mechanisms how to minimize the noise and ensure that circuits are stable. Here are some of the measures that diode manufacturers deploy t reduce noise.
One of the causes of diode noise is temperature. Great variations in temperature will have a direct impact on the behavior of the diodes. To curb this problem, you will have to implement various temperature regulation techniques in the circuit. Installing cooling systems such as fans is one of the effective ways of thermal regulation. You should also look at the operating temperature when selecting diodes to ensure that it will remain stable when installed in the circuit.
After installing diodes in the circuit, you can add various filtering techniques in the circuit. These measures are taken to shield sensitive components from the effect of the current and signals generated by the diode noise. Noise shielding can be implemented when designing circuits for the diodes.
Using quality diodes
You can prevent the diode noise by buying low-noise diodes for sale. Some diodes have internal mechanisms to prevent or minimize the generation of noise when in operation. All you need to is find a reliable diode supplier and check out their catalog of low-noise diodes.
Why should I filter diode noise?
Now that you know what diode noise is and its causes, let’s look at some top reasons why there is a need to filter diode noise.
The main reason for filtering diode noise is to improve the quality of signals. Let’s take an example of diodes that are used in audio systems. Diode noise will interfere with the main signal leading to the generation of unwanted noise. Noise filtering mechanisms have to be introduced in the circuits to ensure that the output signal is of good quality. For an audio application, listeners should be able to get clear sound from the devices.
Another reason behind filtering of the diode noise is to enhance the safety of the device or circuit. In some cases, the diode noise could lead to the leakage of current from the circuit. The leaked current may end up damaging sensitive components in the circuit and diode. By deploying appropriate filtering mechanisms, you will be able to prevent electrical and mechanical damage due to the diode noise.
Filtering also improves the accuracy of the electronic devices. Some diodes are used in measuring devices and each value that is measured matters. The generation of the noise may interfere with the signals used for the measurement. The overall effect will be inaccurate readings. With proper filtering mechanisms, it will be easy to get precise readings from the devices.
I hope that with this information about diode noise, you should be in a perfect position to make the right decisions when it comes to the selection of diodes for your applications.
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