LED is the abbreviation of light emitting diode. LED is being widely used with the development of economy and technology. In this paper, I will introduce the application of LED in the aspect of indicator light in the circuits. 1.A indicator light of AC power supply As long as the circuit is connected with 220V/50Hz AC power supply, LED will be lit, which represents the power supply is switch on. The resistance value of the current-limiting resistance R is 220V/IF. 2.A indicator light of AC switc...(more)
Light Emitting Diode (LED) is a kind of semiconductor solid light emitting device, which uses solid semiconductor chips as light emitting materials.When applying a positive voltage at its both ends, the composite of carriers in semiconductor will induce photon emission and produce light. LED can directly emit red, yellow, blue, green, green, orange, purple and white light. There are many advantages of LED product. 1.High efficiency: spectrum can almost concentratein the range of visible light fr...(more)
The thermistor is a kind of sensitive elements. According to the different temperature coefficients, it is divided into positive temperature coefficient thermistor (PTC) and negative temperature coefficient thermistor (NTC). The typical characteristic of the thermistor is sensitive to temperature, and it shows different resistant values under different temperatures. With the increase of temperature, the resistant value of PTC will be larger and with the decrease of temperature, the resistant val...(more)
Thermistor is a resistor whose resistance value is very sensitive to temperature. It is also known as semiconductor thermistor. The main characteristics of thermistor is high sensitivity to temperature, small thermal inertia, long service life, small volume, simple structure, and various shapes, which has become the sensitive resistor used very widely. There are many kinds of thermistor. According to the resistance temperature coefficient, it can be divided in two categories: positive temperatur...(more)
TEC have both cooling and heating functions. Its working current is DC current, through changing the polarity of the direct current, the TEC can achieve cooling or heating. TEC has the following advantages and characteristics in the field of technology. 1. There is no need in using refrigerant, and TEC can work continuously. It doesnt have gyroscopic effect because there are no rotating parts. And when it works, it has such characteristics as no vibration and noise, long life and easy installati...(more)
The NTC element is a negative temperature coefficient thermistor, which is widely used in radio production. This paper mainly introduces the applications of the following three aspects. 1. Temperature compensation in instrument circuit In the instrument circuit, there are a lot of elements with metal wire, which is like wire wound resistance. As metal wire generally has a positive temperature coefficient, using NTC for temperature compensation, errorsproduced bytemperature changes can be offset....(more)
Thermistor is one of thermal resistors, and the principle is that the resistance change is caused by the change of temperature. But now, the thermal resistor has generally been industrialized, which is basically refers to the PT100, CU50 and other commonly used thermal resistors. The difference between these two kinds of resistance: the thermal resistance is generally refers to the metal thermal resistance (PT100, etc); Thermistor is a semiconductor thermal resistance. The temperature coefficien...(more)
There is no screwdriver with round head because the round head has no torque.The flat headscrewdriver is to ensure the torque, and the Phillips screwdriver can distribute power uniformly.According to the power source, screwdriver can be divided into manual screwdriver and electric screwdriver; According to the shape of cutter head,it can be divided into flat head screwdriver and Phillips screwdriver. The cutter head ofgood quality screwdriver is made of spring steel with relatively high hardness...(more)
