020 Introduction of common electronic components (E)

Introduction of common electronic components (E)

1. Resistors (5)

E. Thermistor
Thermistor: A sensor resistor whose resistance varies with temperature. According to the different Temperature coefficients, it can be divided into Positive Temperature Coefficient Thermistor (PTC, that is, Positive Temperature Coefficient Thermistor) and negative Temperature Coefficient Thermistor (NTC, Negative Temperature Coefficient Thermistor). Positive temperature coefficient thermistors, whose resistance increases with increasing temperature, and negative temperature coefficient thermistors, whose resistance decreases with increasing temperature, both belong to semiconductor devices.

F. Photosensitive resistors
Photosensitive resistance: also known as photoconductive tube, commonly used materials for the production of cadmium sulfide, in addition to selenium, aluminum sulfide, lead sulfide, bismuth sulfide and other materials. These materials have the property of rapidly decreasing resistance under certain wavelengths of light. This is because the charge carriers generated by light are involved in conduction and drift under the action of the applied electric field. Electrons run to the positive pole of the power supply, and holes run to the negative pole of the power supply, so that the resistance value of the photosensitive resistor drops rapidly. According to the spectral characteristics of photoresistors, they can be divided into three kinds of photoresistors: ultraviolet photoresistors, infrared photoresistors and visible light photoresistors.

G. Metal Film Resistors
Metal Film Resistors: One of the Film Resistors. It adopts high temperature vacuum coating technology to attach nickel-chromium or similar alloy to the surface of the porcelain rod to form a skin film. After cutting and adjusting the resistance value, the final precision resistance value is achieved. Then, appropriate joint is added to cut and the surface is coated with epoxy resin seal protection. Because it is a lead resistance, convenient manual installation and maintenance, used in most household appliances, communications, instruments and meters. Its heat resistance, noise potential, temperature coefficient, voltage coefficient and other electrical properties are better than carbon film resistors. Compared with the carbon film resistor, this resistor has small volume, low noise, good stability, but high cost. It is often widely used as a precision and high stability resistor, and is also widely used in various radio and electronic equipment. The metal film resistor is shown in the figure below.

Post time: May-29-2022