Every electronic device works according to its specifications. Using them in the design of various devices of any complexity, you can make a mathematical model of a device. On this principle, programs have been created that use mathematical modeling and allow you to see the operation of an electronic circuit on a monitor screen. They greatly help in the development of devices. Connecting virtual nodes to various nodes
oscilloscopes, you can make sure that the future product is working and, if necessary, make adjustments. On their basis, you can not only learn how to design electronic devices, but also study some features in the operation of elements, deepen your theoretical knowledge. As an example, we can consider one of the basic elements in electronics based on the current-voltage characteristic, hereinafter the CVC of a diode. These devices are good because there are several types of them. All of them are successfully used in electronic circuits. These devices have proven themselves over the years of operation in equipment for various purposes.
For the first time such an element was assembled in its“tube” version and for quite a long time was used in the design of various circuits. Such devices are used in tube amplifiers, which are still produced by individual companies. The CVC of the diode in this case is described by the Boguslavsky-Langmuir formula. According to this formula, the current flowing through the device is directly proportional to the voltage to the power of three second, multiplied by a factor. As you can see, there is a nonlinearity in the initial section of the CVC of the diode. This curve “straightens out” when the operating point of the nominal parameters is reached.
The parameters of the semiconductor device are almost close to ideal. The nonlinearity in the initial section depends on the material from which the crystal is made. Also of great importance is the amount of impurities, that is, the quality of raw materials. The IV characteristic of a semiconductor diode can be represented as a curve that varies approximately exponentially and has an inflection point before it reaches its operating characteristic. In silicon samples, the operating point "breaks" at the level of 0.6-0.7 volts. It is closest to the ideal CVC value of the Schottky diode, here the output point for the operating characteristic will be in the region of 0.2-0.4 Volts. But it should be borne in mind that at a voltage of more than 50 volts, this property disappears.
The so-called zener diode has a curve “inverse” to a conventional element. That is, when the voltage increases, the current practically does not appear until a certain threshold is reached, after which it increases like an avalanche.
The manufacturers of these items try not to specify the exactcharacteristics, since they differ quite a lot even within the same batch. In addition, you can take a diode whose I-V characteristic is accurately measured in the laboratory and change its operating temperature. And the characteristics will change. Usually, some limits for the stable operation of an electronic element are indicated, depending on the conditions of its operation.
