Because coils are divided into homonymous and non-homonymous ends.
Color-coded inductors are similar to color-coded resistors in that they use different colors to represent different numbers, which can indicate how much inductance the inductor has. Some inductor values are labeled directly on the inductor package; some require a meter to measure.
1. Classification of Inductors: Commonly used inductors are fixed inductors, trimmer inductors, and color-coded inductors. Transformers, choke coils, shock coils, deflection coils, antenna coils, mid-period, relays, and delays and magnetic heads, etc., all lose inductor types. 2, the main technical indicators of inductors Inductance: L 3, inductor marking methods: a. Indicator method. b. Digital representation. c. Color code representation. This method of expression is also similar to the resistor color code method, the color code generally have four colors, the first two colors for the effective number, the ground three colors for the multiplier, the unit is uH, the fourth color is the error bit
Wire-wound resistors are made of resistor wires wrapped around an insulating skeleton. The resistance wire is generally made of nickel-chromium, manganese-copper and other alloys with a certain resistivity. The insulating bobbins are made of ceramics, plastics, insulating-coated metals, and other materials in various shapes such as tubular and flat. Resistor wire in the skeleton according to the need to wind a layer, can also be wound multi-layer, or non-inductive winding method. This kind of resistance is divided into two kinds: fixed and variable. It is characterized by stable operation, good heat resistance, small error range, resistance value can be accurate to 0.001 ohm, more expensive, mostly used in medical equipment, rated power is generally more than 1 watt. Wirewound resistors are accurate, theoretically speaking, unless the charger output voltage reference, general chargers do not use wirewound resistors. Charger circuit for SMPS switching power supply circuit, the high voltage end of the signal generating circuit is very demanding, it is not possible to use wirewound resistors, otherwise it will lead to self-excitation, which affects the oscillation frequency, thus making the output fluctuation is large, only the low-voltage end of the sampling reference circuit may use wirewound resistors. Wear and tear can cause localized thinning of the wire diameter, and in the case of long-term use of energized, the long-term action of the current changes the intrinsic composition of the wire, thus making the resistance value smaller.
In short a color coded resistor is a resistor whose resistance value is indicated by five different colored rings on the outside
A wirewound resistor is a slide wire varistor.