Basic introduction of power winding resistance and several resistors

The power wirewound resistor is a two-terminal electronic component made of a resistive material and having a certain structure and capable of limiting the passage of current in the circuit. A resistor cannot be changed and is called a fixed resistor. A variable resistance is called a potentiometer or a variable resistor. The ideal resistor is linear, ie the instantaneous current through the resistor is proportional to the applied instantaneous voltage. Some special resistors, such as thermistors, varistors, and sensitive components, have a non-linear relationship between voltage and current. Resistors are the most widely used components in electronic circuits. They are usually formed in different series according to power and resistance for circuit designers to choose. The resistor is mainly used in the circuit to regulate and stabilize the current and voltage. It can be used as a shunt and a voltage divider, or as a circuit matching load.

According to the circuit requirements, it can also be used for amplifying the circuit's negative feedback or positive feedback, voltage-current conversion, input voltage or current protection components, and RC circuit as oscillation, filtering, bypass, differential, integral and time constant. Components, etc. The function of the low-power carbon film resistor is usually composed of a carbon film encapsulated in a plastic case, and the resistor of the power wire-wound resistor is usually a wire wound resistor, which is made by winding a wire of large resistivity on the porcelain core. .

If the resistance of a resistor is close to zero ohms (for example, a large-section wire between two points), the resistor has no effect on the current, and the circuit in which the resistor is connected is short-circuited, and the current is infinite. If a resistor has an infinite or large resistance, the loop in series with the resistor can be considered an open circuit with zero current. Resistors commonly used in the industry are between two extremes. They have a certain resistance and can pass a certain current, but the current is not as large as the short circuit. The current limiting action of the resistor is similar to the effect of limiting the flow of water by a small diameter tube connected between two large diameter tubes.

Resistance, the English name resistance, usually abbreviated as R, is a basic property of a conductor, related to the size, material, and temperature of the conductor. Ohm's law says, I=V/R, then R=V/I, the basic unit of resistance is ohm, expressed by the Greek letter “Ω”, with the definition that one ampere current is generated when a voltage is applied to the conductor. The corresponding resistance value. The main function of the resistor is to block the flow of current. In fact, "resistance" refers to a property, and the resistance usually referred to in electronic products refers to a component such as a resistor.