In the application field of electronic components, non-inductive resistors play an important role. As the name suggests, "non-inductive" means that this type of resistor has a very small inductive reactance value, to the extent that it can be ignored. Although it cannot be said that they have no inductive reactance at all, in many precision electronic equipment, non-inductive resistors are used to avoid circuit oscillation and damage to other devices that may be caused by ordinary high inductive reactance resistors.
The definition and function of non-inductive resistors
Non-inductive resistors are often used as loads in electronic devices to absorb or buffer unwanted electricity. This resistor is also often called a brake resistor or load resistor. In high-precision electronic equipment, the existence of high impedance is usually not allowed, so it is necessary to choose non-inductive resistors made of high-quality materials and precision processes. Common non-inductive resistor types include metal film resistors, wirewound resistors and TO-220 high-power load resistors.
How non-inductive resistors work
The manufacturing process of non-inductive resistors involves a special winding technique. Fold the two wires of the resistor in half and connect them to the two terminals of the resistor base. The remaining wires are wound around the resistor base. Since the spiral wires during winding are positive and negative, the inductance generated is opposite in polarity, thereby canceling each other out, achieving a non-inductive effect. This is the basic method to achieve the function of a non-inductive resistor.
Specific applications of non-inductive resistors
The main function of a non-inductive resistor is to allow only the resistance of the wire or coil to work without producing inductance or induced voltage. In practical applications, a common practice is to place two insulated wires side by side, short-circuit one end and connect the other end to the power supply and application lines. Since the current directions in the two wires are opposite and there is no external mutual inductance, they can be wound into a coil and act only as resistors. For example, in the stator slot of large AC motors, non-inductive resistors are often buried for temperature measurement.