1, According to the wire color marking circuit
Black - internal wiring of devices and equipment.
Brown - the positive pole of the DC circuit.
Red - phase C of a three-phase circuit; collector of a semiconductor transistor; cathode of a semiconductor diode, rectifier diode or thyristor.
Yellow - phase A of a three-phase circuit; base of a semiconductor transistor; control pole of a thyristor and a triac.
Green - Phase B of a three-phase circuit.
Blue - the negative pole of the DC circuit; the emitter of the semiconductor transistor; the anode of a semiconductor diode, a rectifier diode or a thyristor.
Light blue - the neutral or neutral of a three-phase circuit; the grounded neutral of a DC circuit.
White - the main electrode of the bidirectional thyristor; no semiconductor circuit of the specified color.
Yellow and green two colors (each color is about 15 to 100 mm alternately attached) - a safe grounding wire.
Red and black parallel—AC circuits connected by twin-core or double stranded wires.
2. When selecting the color of the wire according to the circuit
AC three-phase circuit
Phase A: yellow; Phase B: Green; Phase C: Red;
Neutral or neutral: Light blue; Safety ground wire: yellow and green.
AC circuit connected by double-core wire or double stranded wire
Red and black are parallel.
Positive: brown; negative: blue; grounded neutral: light blue.
Collector of semiconductor transistor: red; base: yellow; emitter: blue. Anodes of semiconductor diodes and rectifier diodes: blue; cathode: red.
Anode of thyristor tube: blue; control electrode: yellow; cathode: red.
Semiconductor circuit color
Control electrode of the two-way thyristor: yellow; main electrode: white.
Internal wiring of the entire device and equipment is generally recommended: black; semiconductor circuit: white;
When there is confusion: allow the selection of other colors outside the color (such as: orange, purple, gray, green blue, rose, etc.).
On a wire, if there are two or more kinds of calibratable colors, depending on the specific conditions of the circuit, the color is fixed according to a certain meaning that needs to be expressed in the circuit.