A screwdriver is used to turn the screws and force them in the place. There is usually a thin wedge head, which can be inserted into the screw head slot or recess. The screwdriver shape is mainly divided intwo types:slotted screwdriver and cross screwdriver. The six angle screwdriver is also very common, whichincludes inner six anglescrewdriver and outersix corner screwdriver.(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.A good screwdriver should meet thedemand of appropriate hardness and toughness.When the groove of screw head goes bald, we can use a hammer to hit a screwdriver, and then the groove will become deep, and it will be easy to twist the screw out, but the screwdriver should be unscathed. A screwdriver is often used to pry the things, so it requires certain toughness.Generally speaking, the screwdriver head hardness should be greater than HRC60, which is not easy to rust.(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 coefficient of semiconductor thermal resistance is more than 10 to 100 times as big as that of metal, and it can detect the temperature change of 10~6℃ and select the resistance value of 0.1 ~ 100kΩ. That is why the semiconductor thermal resistance is called thermistor. The thermistor is generally used in circuit boards. It can be used as a protective device because the resistance changes with the change of temperature. Of course, this is only one aspect. There are many other uses of thermistor. For example, thermistor is used for the temperature compensation of the cold end. However, because of the obvious nonlinear relationship between the resistance and temperature, the consistency of the elements is very poor and it can not have a standard signal as the heat resistance does.(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.(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.(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.(more)
LED is the abbreviation of Light Emitting Diode, which uses solid semiconductor chips as light materials. When adding forward voltage to its two ends, carriers in semiconductors will campsite and release extra energy, which can cause photon emission and generate visible light. The advantage of LED including: efficient and energy-saving, long service lifetime, health light, green environmental protection and so on.(more)
Thermoelectric cooler (TEC), which was first found by Peltier in 1834, is a semiconductor material as the foundation, and it can be used as electronic components of a small heat pump. Through loading a low DC voltage on both ends of the TEC, the heat will move from one side of the element to the other. At this time, the temperature of one side of TEC will be reduced, and the other side temperature will rise. It is worth noting that, as long as the direction of the current is changed, the direction of heat flowcan be changed and the heat will be conveyed to the other end. So TEC can realize two functions of refrigerating and heating at the same time. In addition, TEC can also be used to control temperature precisely.(more)
Power Supply can convert another form power into electrical energy. The generators convert mechanical energy into electrical energy, dry cell convert chemical energy into electrical energy. The battery itself has no electricity. There are positive and negative charges on its two poles. They will provide voltage; electrical conductor has voltage in itself. When we add voltage, it will produce electricity. When the battery’s two poles connect with conductor, it releases charge so that generate electricity. Dry cell also called power supply, there is equipment called eliminator supply convert alternating current into direct current through transformer and rectifier. There is equipment called signal source provide signal. Triode transistor amplification signal which is send before, then we sent signal which it be amplification to circuit in return. We regard triode transistor as signal source to circuit in back. Rectified current, signal source sometimes also called power supply.(more)
