R03 Carbon battery.The role of cement resistors in power circuits and frequency dividers

　　Cement resistors are made by winding the resistance wire around a non-alkali heat-resistant porcelain piece. The outside is protected and fixed with heat-resistant, moisture-resistant and corrosion-resistant materials. The wire-wound resistor body is placed in a square porcelain frame, and is made of special non-combustible heat-resistant materials. It is filled and sealed with cement. The outside of the cement resistor is mainly made of ceramic material (generally divided into high alumina porcelain and feldspathic porcelain).

　　A cement resistor is a resistor potted with cement (actually not cement but refractory mud, as it is commonly known). The resistor wire is wound around a non-alkali heat-resistant porcelain piece, and the outside is heat-resistant, moisture-resistant and corrosion-resistant. The material is protected and fixed, and the wire-wound resistor is placed in a square porcelain frame, which is filled and sealed with special non-flammable and heat-resistant cement. There are two types of cement resistors: ordinary cement resistors and cement wire-wound resistors.

　　Cement resistors are a type of wirewound resistors. They are high-power resistors and can allow large currents to pass through. Its function is the same as that of a general resistor, except that it can be used in situations with large currents, such as being connected in series with a motor to limit the starting current of the motor. The resistance value is generally not large. Cement resistors have the characteristics of large size, shock resistance, moisture resistance, heat resistance, good heat dissipation, and low price. They are widely used in power adapters, audio equipment, audio frequency dividers, instruments, meters, televisions, automobiles and other equipment.

　　Characteristics of cement resistor:

　　1. Shock resistance, moisture resistance, heat resistance, good heat dissipation, low price and other characteristics.

　　2. Completely insulated, suitable for printed circuit boards.

　　3. Wind the wire around the porcelain rod and then weld the joints to produce accurate resistance values and extend service life.

　　4. The high resistance value is made of metal oxide film (MO) instead of winding.

　　5. Excellent heat resistance, small resistance temperature coefficient, linear change.

　　6. Resistant to short-term overload, low noise, and no change in resistance over the years.

　　7. Good explosion-proof performance and protective effect.

　　The role of cement resistors in power circuits:

　　1. The power supply current limiting function is usually connected to the main voltage +300V and the E and C poles of the power switch tube. The function is to prevent the power supply from being destroyed and damaging its components when the power is turned on.

　　2. The power supply starting resistor, the resistor between the power tube and the starting circuit is connected across +300V. The voltage drop and current are large, so cement resistors with larger power are also used.

　　3. The peak pulse absorption circuit between the B, C, and E poles of the power switch tube also uses high-power cement resistors, which also protect the power switch tube.

　　4. The current protection circuit is generally connected between the E pole of the power switch tube and the ground. When working normally, its resistance can be ignored, because the resistance of the resistance is very small and there is no current. It only occurs when the circuit itself is short-circuited with the load. , in order to increase the current of the E pole of the power switch tube, a protection voltage is generated at both ends of the resistor to start the related circuit.

　　The role of cement resistors in frequency dividers:

　　1. Attenuation;

　　2. Form an impedance compensation network with the capacitor.

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