We can find 3 types of jack connector, monaural TS connector (tip-sleeve), TRS (tip-ring-sleeve) and TRRS stereo plug (tip-ring-ring-sleeve) which is used in most mobile devices, tablets, MP3 etc ...
We can difference these 3 types of connectors according to their diameter:

1. 6.35 mm jack connector or TS.
2. 3.5mm minijack connector or TRS, is the most common, usually used in headphone's output of portable devices.
3. 2.5mm jack connector or TRRS.

It consists of a maximum of three connecting parts being called the largest mass or negative polarity and two smaller size located more towards the end of the connector,
The called positive that correspond to each channel, such three-part plug can transmit signals in two separate channels, also known as stereo signals. There's a mono version, consisting of only two parts, a negative and a positive.

A. Protector
B. Stem
C. Ring
D. Tip
E. Kindred
F. Ring (Signal Right)
G. Tip (Signal Left)

VDC would be the abbreviation for Volt Direct Current which translated would volts direct current. The idea of ??this type is unidirectional current to the load. Direct current is normally produced by batteries, thermocouples, solar cells and a dynamo electric machine type. The direct current can flow in conductors such as wires, but may also flow through semiconductors, insulators ... In the image: 1 - current per pulse 2 - Direct Current (DC) 3 - Alternating Current (AC) 4 - Variable Current

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