Small power is usually packaged in a carbon film encapsulated in a plastic housing, and a high power resistor is typically a winder resistor, which is made by looping a wire of a large resistivity on a porcelain heart. If a resistor resistance The value is close to zero ohms (eg, large cross-sectional wires between two points), then the resistor does not hinder the current, and the circuit of such a resistor is short-circuited, and the current is infinite.
If a resistor has an infinite or large resistance, the loop of the resistor can be viewed as an open circuit, and the current is zero. The resistor commonly used in the industry is between two extreme conditions, which has a certain resistance, which can be largely used by a certain current, but the current is not as large as a short circuit. Restricted limiting effects of resistors are similar to the active flow of small diameter tubes between two large diameter pipes.
Resistors are generally called resistors in daily life. Is a current limiting element, after the electrical blocking is in the circuit, the resistance of the resistor is fixed, which is generally two pins, which can limit the current size of the branch therebetween. The impedance resistor cannot be changed. The resistance variable is called a potentiometer or variable resistor. The ideal resistor is linear, that is, the instantaneous current of the resistor is proportional to the external transient voltage. Variable resistors for partial pressure.
The resistance value of the resistance element is generally related to temperature, material, length, as well as a cross-sectional area, and measuring the physical quantity of the temperature of the electric resistance is a temperature coefficient, which is defined as a percentage of the resistance value at a temperature of 1 ° C per liter. The main physical characteristics of the resistor are thermal energy, which can also be said to be a energy consuming component, and the current can produce internal energy. The resistor usually sends a partial pressure and shunt in the circuit. For signals, the AC and DC signals can pass the resistance.