Connector Basics

(1st draft Sunday, April 26, 2015)

 

Introduction - A connector is required to join 1 or more wires to another wire or to make secure connection to an electrical termination. This article attempts to define general terms and conventions into basic working definitions for sharing between CASA Modular Systems and its customers.

 

There are more different connectors in the world today than were ever dreamed about 10 years ago and the proliferation seems to be continuing to escalate in spite of the greater integration and miniaturization of electronic systems. Connectors are a vital component for making electronics possible and reliable. Indeed, connectors make the whole world of electrics and electronics possible.

 

Reliability is being achieved by better designs, better materials-technology, better machining equipments, automation of assembly and quality control etc.

 

There are many good/classical connector designs invented during and post WWII that have become industry standards and these have only been improved by better materials and machining technologies. New connectors arise form the demands for miniaturization and the demand for lower costs and the demands for greater mating life and general reliability.

 

Connector Philosophy – according to the theory of quantum entanglement, everything in the cosmos (and elsewhere) is connected; however, to facilitate our inventions we humans need to build purpose-designed connectors to perform our special requirements. Better connectors evolve according to our desires and our needs.

 

Our primitive connectors serve us pending discovery of the ultimate-connector that connects everything to everything else J

 

If humanity is to survive the gross inefficiency of our primitive energy management we will need to design a ‘connector’ that will better ‘connect’ us to the sun (as the prime energy source that sustains us) J

 

Definitions:

 

Connectors help facilitate the transfer of signals and/or energy from one conductor to another with improved efficiently compared to hard-wiring.

 

A connector (electrical) is a device for making connection to or in (between) electrical circuits (or equipments).

 

 

Component Parts – there are up too 4 principal components and various auxiliary parts to suit specific mechanical and electrical needs:

 

1.     A connector comprises a contact which facilitates a composite connection to a wire such that the wire may be connected to another connecter or termination with improved electrical integrity. Where such contacts mate with a corresponding contact they may be referred to as pin-contacts and socket contacts according to the physical form.

 

                         

 

2.     A connector may have an insulated-container to hold the contact at a safe working distance from another contact or terminal.

3.     A connector may have a body or shell, sometimes integrated with the insulator, to facilitate mechanical engagement or retention of the mated contacts.

4.     A connector body may have cable clamping accessories to eliminate un-wanted stress on the connected wires and cables, These are often called back-shells.

 

Contact Sizes & Wire & Cable Gauges

 

Dimensions – the contact of a contact may be defined by its physical size and a cable as a cross-sectional equivalent of the conductors or by its effective diameter, or by its standardized gauge (typically AWG).

 

 

 

Contacts - There are 3 basic contact types:

 

1.      Pin contacts (install into socket-contacts)

 

   

 

2.      Socket contacts (accept pin-contacts)

 

   

 

3.      Hermaphrodite contacts - (sex-less such as EDAC 516 series)

               

Contact size is frequently denoted by a figure which corresponds to the diameter of the active part of the pin/socket or as a standardized gauge (typically AWG or mm2 cross-section). The table below is a guide to wire sizes and capacities.

 

Current - the current carrying capacity of a connector is determined by the pin~socket interface and the gauge of the wire connected to it. Other factors include; contact material, operational environment, surface plating, mating surface integrity and insertion (mating) life.

 

The gauge of a contact, and its assigned wire, determine the limits of current carrying capacity and are variably proportional to the maximum working current.

 

Voltage – the working voltage of a connector is primarily determined by the insulation that surrounds it and the distance to other contacts or conductors.

 

Gauge - is expressed by an integer or figure, which corresponds to the section of the conductor core according to the referential standard from which it is derived.

 

American Wire Gauge

Diameter

Diameter

Cross Sectional Area

Current (maximum)

(AWG)

(inches)

(mm)

(mm2)

(Amps)

0000

0.46

11.68

107.16

380

000

0.4096

10.4

84.97

328

00

0.3648

9.27

67.4

283

0

0.3249

8.25

53.46

245

1

0.2893

7.35

42.39

211

2

0.2576

6.54

33.61

181

3

0.2294

5.83

26.65

158

4

0.2043

5.19

21.14

135

5

0.1819

4.62

16.76

118

6

0.162

4.11

13.29

101

7

0.1443

3.67

10.55

89

8

0.1285

3.26

8.36

73

9

0.1144

2.91

6.63

64

10

0.1019

2.59

5.26

55

11

0.0907

2.3

4.17

47

12

0.0808

2.05

3.31

41

13

0.072

1.83

2.63

35

14

0.0641

1.63

2.08

32

15

0.0571

1.45

1.65

28

16

0.0508

1.29

1.31

22

17

0.0453

1.15

1.04

19

18

0.0403

1.02

0.82

16

19

0.0359

0.91

0.65

14

20

0.032

0.81

0.52

11

21

0.0285

0.72

0.41

9

22

0.0254

0.65

0.33

7

23

0.0226

0.57

0.26

4.7

24

0.0201

0.51

0.2

3.5

25

0.0179

0.45

0.16

2.7

26

0.0159

0.4

0.13

2.2

27

0.0142

0.36068

0.102

1.7

28

0.0126

0.32004

0.081

1.4

29

0.0113

0.28702

0.0642

1.2

30

0.01

0.254

0.0509

0.86

31

0.0089

0.22606

0.0404

0.7

32

0.008

0.2032

0.032

0.53

 

 

For a given size, a contact theoretically can only accommodate wires having a section included between a minimum and a maximum.  This min/max range can sometimes be extended upward by boring the barrel without increasing its outside diameter and downward by adapting an inside diameter reducing sleeve. Those specific adaptations need to be guided by manufacturer’s data etc.

 

Density - The number of contacts in a connector is defined by the arrangement. The outside diameter across insulation of admissible conductors is limited by a   minimum and a maximum.  Those limits depend on mechanical and sealing requirements specified for insulators and elastomers.

 

Sex or Gender – for the convenience of definition, connectors have ‘sex’ (or at least they have gender), however, there are hermaphrodite (sex-less) connectors and so much diversity in design arrangement and contact-interchange which can cause confusion if some conventions are not established and disciplined (in the associated description).

 

Where there is no external container for the contacts then there is no risk of confusion, however, electrical connectors most frequently have mouldings for insulation and mechanical retention of the mated connector pair. These accessories for the contacts tend to be variable/diverse creations to suit specific engineering applications. In this diversity there is diversity in connector-sex definitions.

 

For the purposes of modern technology a majority of electronic connectors have shells that contain the contacts. Few connectors for PCB interconnect are un-housed and few are sex-less (with abutting or hermaphrodite contacts)

 

Polarisation – to eliminate miss-mating of similar multipole connectors, various forms of polarization have been adopted. Polarisation may be achieved by 3 different methods:

 

1)     body-polarisation; when the insulating body of a connector constrains the matching and elimitatesmiss-matching

2)     contact-polarisation; where the arrangement or sex of contacts is arranged to constrain the connector mating

3)     shell polarisation; where the outer container of a connector is keyed or otherwise shaped or arranged such that it eliminates mating except with its matching opposite sex connector shell.

 

 

CASA does not agree with Wikipedia which seems to have chosen to adopt the ‘rules’ for plumbers and mechanical engineering:

 

http://en.wikipedia.org/wiki/Gender_of_connectors_and_fasteners

 

It is CASA’s opinion that the ‘sex’ is established 1st (regardless of the mounting/fixing arrangement) by the predominant electronics conventions of atypical plugs and atypical sockets…. …..otherwise, among the typical confusions are:

 

·         “Jacks without ”Jills”…

·         “free-plugs” and “cable-plugs”…

·         “fixed-jacks” and “free-jacks”…

·         “receptacles” mate with what?

·         “Jacks” with pin-contacts and socket-contacts or a mixture thereof…

·         “Plugs” with socket-contacts and pin-contacts or a mixture thereof….

·         There are male-plugs and female-plugs?

·         There are various other confusing combinations of terms that fail to make a concise and adequate definition that does not tale a picture to qualify.

·         Connectors may plug-into or plug-onto the mating sockets

 

CASA adopts the most common-usage rule that recognises:

 

The gender of any connector is established by the ‘common-usage’ outer mating interface.

 

This is an atypical PLUG…..   …..This is an atypical Socket

 

 

 

 

The common-usage says:

 

·         A plug plugs in-to or on-to something (such plugs are commonly cord attached and now-a-days, may have pin or socket contacts)

·         A socket is what a plug gets plugged into (such sockets are commonly cord attached and now-a-days, may have pin or socket contacts)

·         Connectors are generally cable or chassis mounting (PCB and other fixing accepted) – the cable-mounted connector generally has an insulated housing suitable to the number of contacts being deployed.

 

 

In the field of electronics Plugs plug onto sockets and inner contacts-arrangements are a secondary variable that does not represent the major component of the connector assembly.  

 

Plug (alias: male) – the outer coupling-body fits over the mating (jack/female) connector part

Socket (alias: jack/female) – coupling-the body installs into the larger/mating (plug/male) connector part

 

References:

 

https://learn.sparkfun.com/tutorials/connector-basics

 

http://www.thomasnet.com/articles/automation-electronics/basic-electrical-connectors

A video tutor:

https://www.udemy.com/tech101-cables-and-connectors/

Wiki:

http://en.wikipedia.org/wiki/Connector

 

 

CASA eSales

http://www.casa.co.nz

or, our on-line eSales development site:

http://www.casamodularsystems.com