Different functions and applications of resistors with different powers

Aguilera

Different functions and applications of resistors with different powers [Copy link]

Resistors are generally called resistors in daily life. It is a current limiting element. After the resistor is connected to the circuit, the resistance of the resistor is fixed, usually with two pins, which can limit the current through the branch it is connected to. The resistor whose resistance cannot be changed is called a fixed resistor. The resistor whose resistance is variable is called a potentiometer or a variable resistor. The ideal resistor is linear, that is, the instantaneous current passing through the resistor is proportional to the applied instantaneous voltage. Variable resistors used for voltage division. On the exposed resistor body, one or two movable metal contacts are pressed tightly. The position of the contact determines the resistance between any end of the resistor body and the contact. The two-terminal device that has a definite functional relationship between the terminal voltage and the current and reflects the ability to convert electrical energy into other forms is represented by the letter R, and the unit is ohm Ω. Actual devices such as light bulbs, heating wires, resistors, etc. can all be represented as resistor elements. The product information of the eddy current displacement sensor merchant shows that the resistance value of the resistor element is generally related to temperature, material, length, and cross-sectional area. The physical quantity that measures the influence of temperature on resistance is the temperature coefficient, which is defined as the percentage change in resistance value when the temperature rises by 1°C. The main physical characteristic of a resistor is to transform electrical energy into thermal energy. It can also be said that it is an energy-consuming element, and internal energy is generated when current passes through it. Resistors usually play the role of voltage division and current shunting in circuits. For signals, both AC and DC signals can pass through resistors. Low-power resistors are usually made of carbon film encapsulated in a plastic shell, while high-power resistors are usually wound resistors, which are made by winding a metal wire with a high resistivity around a porcelain core. If the resistance value of a resistor is close to zero ohms (for example, a large cross-section wire between two points), the resistor has no obstruction to the current, and the circuit connected in parallel with such a resistor is short-circuited, and the current is infinite. If a resistor has infinite or very large resistance, then the circuit connected in series with the resistor can be regarded as an open circuit, and the current is zero. The resistor commonly used in industry is between the two extremes. It has a certain resistance and can pass a certain current, but the current is not as large as when it is short-circuited. The current limiting effect of a resistor is similar to the effect of a small diameter pipe connected between two large diameter pipes to limit the flow of water. Resistance, English name resistance, usually abbreviated as R, is a basic property of conductors, which is related to the size, material and temperature of the conductor. Ohm's law says that I=U/R, then R=U/I. The basic unit of resistance is ohm, represented by the Greek letter "Ω", and has the following definition: when a voltage of one volt is applied to a conductor, the resistance value corresponding to the current of one ampere is generated. The main function of a resistor is to hinder 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. Ohm is often abbreviated as ohm. Other commonly used units for expressing resistance values include kiloohms (kΩ), megaohms (MΩ), and milliohms (m Ω).