Cable, Wiring and Connector Guide

Your reference guide for PCB (trace resistivity, footprint) wire (gaage chart), mil/ inch/mm, hole (drill, tap chart), fastener

Edited by Lim Siong Boon, last dated 02-Oct-09.

email:    contact->email_siongboon  



Shortcut to your reference guides and charts

  1. PCB Trace reference
  2. Wire and Cable gauge
  3. Advance conductor
  4. PCB Footprint reference
  5. Tap drilling guide (mm chart)
  6. Common Connector Pin Out
  7. Name of Connectors/Plugs
  8. Name of Cable/Wire


I always have to refer to these dimension references frequently,

and decide to put them up once and for all on this website.

Hope they are useful to you too.




1. PCB Trace reference





Trace resistance guide based on

PCB board 1oz copper at temperature 100˚C. (worst case)


Name Trace width Trace Length ResistanceCurrent
Power Normal 1.27mm 1000mm 0.491.75A
Power Min 0.64mm 1000mm 0.981.20A
Signal Normal 0.38mm 1000mm 1.650.80A
Signal Min 0.25mm 1000mm 2.51Ω0.50A
  mm mm

Conversion calculator might not work on some web browser.


Unit conversion table & calculator between inch, mil, mm, oz.

inch mil mm oz
1 1000 25.4  
0.1 100 2.54  
0.001 1 0.0254  
0.03937 39.37 1  
  1.38 0.035 1oz
inch mil mm oz

Conversion calculator might not work on some web browser.



also Download the wire gauge calculator from UltraCAD Design, Inc



The IC chips, active and passive components are all connected by traces or wire. The traces on the PCB are assume to be of short circuit, which is 0Ω. This assumption is reasonable if it conduct a very small amount of current. When the conductor starts to carry larger amount of current, the voltage drop across the trace could be significant, causing intermediate hardware problem.

If you are expecting a large current flowing through the traces, you have to keep in mind to provide a wider trace to increase the conductivity of the cable. Larger trace width means lower resistance.

For my PCB route software, the defined trace width for power is 1.27mm and signal is 0.38mm. Sometimes there is a need to route the trace through narrow space. In this situation, I would have to use the recommended trace width for power min, and signal min. Usually I will keep this narrow trace as short as possible to avoid higher resistance.

Seldom do I need to worry about traces carrying signal information. I am more worried about the conductor distributing the dc supply to individual circuit zone. Whenever possible, I would provide a wider traces for my 5V and ground supply.

When designing the PCB routing for my power supply, I would use the star topologies. This will ensure a evenly spread for the current distribution, hence lowering the burden of individual traces. I have actually experience such technical issue during my final year school project. The noise problem is somehow reduce after the attempt to improve on the trace routing. Another experience involve power up a remote system about 10m away. The distance is quite near and the power cable is rather thick to me. The voltage at the remote end is found to be too low to power the remote system. We have to double the cable conductor in order to resolved the problem. Our equipment conduct high current of about 20A if I remember correctly. The problem might not be obvious because the high current being drawn might happen during certain hard to determine event. For example, when your system trigger the lightings or motor which draws very high current for a short period of time. The voltage drop cause by the sudden high current draw might cause your system to fail. Therefore the design should always cater for the worst case. Always find out the maximum possible current drawn. Over design the system to ensure that the system will not fail in the worst case scenario. Just to make a note, that I have been referring to dc voltage supply.

For high voltage AC supply, I guess it is a different way of looking at it. My understanding in high voltage system is quite weak.

On the left is the reference table to estimate the resistance of the trace for my PCB routing. I have assume the worst case at temperature 100˚C with the copper layer of 1oz thick. Seldom do you need to refer to this table, unless you have encounter space restriction for your high current carrying traces. It is my usual practise to double the current carrying capacity. 2 times the maximum current I will be expecting. If you have the space, make it wider.

Electrical Resistance Equations:

Resistance = Resistivity x Length/Area



Question 1:

1oz copper PCB, Trace width 0.25mm, Trace length 0.1m, Operating temperature 25˚C


Solution 1:

Copper resistivity at  25˚C is 1.68x10-8Ω.m

Resistance = 1.7x10-8Ω.m  x  0.1m  /  (1oz x 0.25mm)

                 = 1.7x10-8Ω.m  x  0.1m  /  (35um x 0.25mm)

                 = 1.7x10-8Ω.m  x  0.1m  /  (8.75nm2)

                 = 1.7x10-8Ω.m  x  0.0114x109m-1

                 = 0.19


Question 2:

1oz copper PCB, Trace width 0.25mm, Trace length 0.1m, Operating temperature 100˚C


Solution 2:

Copper resistivity at  100˚C is 2.17x10-8Ω.m,

Resistance = 2.2x10-8Ω.m  x  0.1m  /  (1oz x 0.25mm)

                 = 2.2x10-8Ω.m  x  0.0114x109m-1

                 = 0.25


I have also provide the computation for copper resistance for your reference. Taking this opportunity to do further read up in order to explain in a simplified form.

Area is the cross sectional area of the conductor. Just like a water pipe, the larger the cross sectional area, the easier the current is able to flow through.

Resistivity defines the resistance of the material for a unit of length at a certain temperature. The resistivity for the material copper at 25˚C is found to be 1.7x10-8Ω.m

The resistivity changes with temperature. The resistance will increase as the temperature increase. The term for this changing resistivity with temperature is known as the thermal resistivity of that particular material.

The material resistivity would therefore look like a graph curve. They are obtained through test and experiment. For some material, the graph curve could be approximated in the form of equation. This complicated formula describe the resistance behavior of the material under different temperature condition. For copper material, it can be represented from the following equation,

Copper resistivity = ρ0(1+α(Temperature-T0))

= 1.7x10-8Ω.m  x  (1 + 3.9x10-3/˚C  x  (100˚C-25˚C))

= 2.2x10-8Ω.m at a temperature of 100˚C

0 is the material resistivity at T0 temperature>

As you can see from the calculation on the left, the increase in temperature from 25˚C to 100˚C has increase the 0.1m copper trace by 0.06Ω. This is about 30% increase in the resistance.

To keep the topic simple, we will not go into the details of varying temperature. There can be other factor that can affect the resistance of the material.

Here is a quick and simple graph showing the change in temperature in relation with the trace width and the current flowing through it. (taken from the magazine elektor 2010-02). The graph assume the pcb copper trace thickness to be 35um (1oz) & that it is place in a open air environment (not enclosed inside a box/casing). For example, given the trace width of 0.6mm, and a 1.5A current flowing through it, we can expect the copper area to rise by another 10C.

pcb trace width, current, temperature



Some article reference:

PCB trace - HwB, trace vs current graph.pdf


Recommended digital and analog circuit layout on a PCB board.

recommended circuit layout


Recommended trace corner layout.

trace corners


Recommended plane placement.

plane placement

Reference taken from "Op Amps for Everyone".

More PCB layout recommendation can be found in the book "Op Amps for Everyone" from Texas Instruments., Singapore Network Ethernet WiFi RS232 RS485 USB I/O Controller



2. Wire and Cable gauge

I have put up this wire gauge guide for my own reference. Very often there is a need to return to this reference to choose an appropriate cable for use. I have also written an article some time back. Myth about how the cable relate to their resistance. It is taken out from the main webpage but I have place a link here, for anyone who are interested to understand more.

NOTE: The following guideline is a brief guideline for copper ampacity (current rating or current-carrying capacity) of the cable used for power supplying purpose. The ampacity is defined as the maximum current the cable can withstand. Any current higher than that will generate enough heat to burn away  the cable. There are many factor affecting the current capacity of the cable, and it should be compensated accordingly. I would advise to select the cable, with at least double the current-carrying capacity for the intended equipment. Never operate near the cable current-capacity limits. You will never know when, the current overruns. Some of the factors that will affect the current-carrying capacity of a cable are:

- Conductive wire cross section area.

- Wire material. The temperature the material can withstand without melting out.

- Temperature. If the wire/insulator jacket can withstand higher temperature, the cable is able to carry more current.

     - place of installation or the surrounding temperature.

     - material of insulation jacket/skin/cover.

     - how much the cable can dissipate heat

- Stranded or solid wire type. Stranded wire can carry more current than a solid wire for AC type of signal/power. This is due to a phenomenon known as skin effect.



- ayenbee AWG Wire Current Rating guide.pdf

- Wire Chart for 12Volt 24Volt.pdf

- A Guide to Wire and Cable Construction.pdf

230v Cable Size Selector-


The factors involve are quite complex. The table is a simplified reference for myself to select the cables. Always allow a larger safety margin of minimum x2 when you chose your cable. Do take careful note of what you deploy.? There are many other factor, eg screw connections, plug contact which will affects the results. If the cable has the slightest warm, it is quite clear that the cable will be hitting it's limit any time soon.


Wire Cable Description Diameter (mm) Area (mm2) Copper Resistance 20˚C./km Nearest SWG gauge (mm) Nearest AWG gauge (mm)
  11.68 107.2 - - 0000
  10.4 85.03 - - 000
  9.266 67.43 - - 00
  8.252 53.48 - - 0
  7.348 42.41 - - 1
  6.543 33.63 - - 2
  5.827 26.27 - - 3
  5.189 21.15 - - 4

230Vac power cable 16mm2 (absolute maximum 69A)

eg. Sub Mains

4.620 16.77 - - 5
  4.115 13.30 - - 6

230Vac power cable 10mm2 (absolute maximum 52A)

eg. high power showers, cookers & other very high power devices

3.665 10.55 - - 7
  3.264 8.366 - - 8

230Vac power cable 6mm2 (absolute maximum 38A)

eg. showers, cookers & other high power devices

2.906 6.634 - - 9
  2.588 5.261 - - 10

230Vac power cable 4mm2 (absolute maximum 30A, 6.9kW)

eg. low power electric shower

2.305 4.172 - - 11
  2.00 3.10 5.47 14 (2.05) 12 (2.05)
  1.90 2.80 6.05    

230Vac power cable 2.5mm2 (absolute maximum 23A)


1.80 2.60 6.76 15 (1.83) 13 (1.83)
  1.70 2.30 7.57    

Wire copper enameled, Pro-Power ECW1.5. current rating 2.74A

eg. power speaker, transformer, motor

1.60 2.00 8.54 16 (1.63) 14 (1.63)
  1.50 1.80 9.7    

230Vac power cable 1.5mm2 (absolute maximum 16A, 3.6kW)


1.40 1.50 11.2 17 (1.42) 15 (1.45)
  1.30 1.30 13.0   16 (1.29)

230Vac power cable 1mm2 (absolute maximum 13A, 2.99kW)

eg. for light circuit

1.20 1.10 15.2 18 (1.22)  
  1.10 0.95 18.1   17 (1.15)

Audio cable (shielded), Belden 8760

eg. power speaker drive

1.00 0.78 21.1 19 (1.02) 18 (1.02)
  0.95 0.71 24.3    
  0.90 0.64 26.9 20 (0.91) 19 (0.91)
  0.85 0.57 30.2    
  0.80 0.50 34.1 21 (0.81) 20 (0.81)
  0.75 0.44 38.9    
  0.70 0.69 44.6 22 (0.71) 21 (0.72)
  0.65 0.33 51.7   22 (0.64)
  0.60 0.28 60.7 23 (0.61)  
  0.55 0.24 72.3 24 (0.56) 23 (0.57)
Wire Cable Description Diameter (mm) Area (mm2) Copper Resistance 20˚C./km Nearest SWG gauge (mm) Nearest AWG gauge (mm)
Category 5E network cable, 8060-OZZ7FNL from Alcatel

16 strand 0.2mm/strand

Multipurpose 10core shielded. (RS232 communication, data signal), Belden 9540, Belden 9536 (6 core), Belden 9534 (4 core)

0.50 0.20 87.5 25 (0.51) 24 (0.51)
Category 5E network cable


0.45 0.16 108 26 (0.46) 25 (0.45)
Telephone line cable, GC5040 from Pro Power 0.40 0.13 137   26 (0.40)
  0.35 0.096 178 29 (0.35) 27 (0.36)
Ribbon cable, 1.27mm pitch         28
  0.30 0.071 243 31 (0.29) 29 (0.28)
Wire wrapping wire, Ok Industries 0.25 0.049 351 33 (0.25) 30 (0.25)

Wire copper enameled

eg. small magnetic coil, speaker, solenoid, inductor, metal detector coil, small motor.

0.20 0.031 547
32 (0.20)
  0.19 0.028 605 36 (0.19)  
  0.18 0.026 676   33 (0.18)
  0.17 0.023 757 37 (0.17)  
  0.16 0.020 844   34 (0.16)
  0.15 0.018 970 38 (0.15)  
  0.14 0.015 1120   35 (0.14)
  0.13 0.013 1300 39 (0.13) 36 (0.13)
  0.12 0.011 1520 40 (0.12)  
  0.11 0.0095 1810 41 (0.11) 37 (0.11)
  0.10 0.0078 2190 42 (0.10) 38 (0.10)
  0.09 0.0064 2700 43 (0.09) 39 (0.09)
  0.08 0.0050 3420 44 (0.08) 40 (0.08)
  0.07 0.0039 4460 45 (0.07) 41 (0.07)
  0.06 0.0025 6070 46 (0.06) 42 (0.06)

Wire copper enameled (very fine)

eg. transformer coupler for audio/signal, wire for earphone

0.05 0.0020 8750 47 (0.05) 43 (0.05)
Wire Cable Description Diameter (mm) Area (mm2) Copper Resistance 20˚C./km Nearest SWG gauge (mm) Nearest AWG gauge (mm)


Cable Guide (typical cable type and name)          Click the chart for enlarge view.

Chart and images taken from Farnell, RS components and other websites.


      also Download the wire gauge calculator from UltraCAD Design, Inc

Other reference,


Refer to the most current National Electrical Code for further information on the electrical cable standards.






3. Advance conductor


Special material for conductivity connection. Some references for non-traditional or advance conductor materials.


I happen to see some special wire product that I think I should put them in this website for reference.

The follow shows a rubber strip (a black layer sandwich in between the two white layer). It is call the elastomer connector. It is typically used to connect a flat LCD display panel to the pcb board without any soldering. It is quite cool when it was being shown to me for the first time. The LCD and pcb is connected with this elastomer connector sandwich in between.


Elastomer connector

(soft rubber strip that can conduct like a wire)



Conductive fabric or cloth

this pic is tken from other website

The conductive fabric actually can feels like a typical cotton cloth material. Some other feels like a nylon fabric, a bit like plastic. This is great for RF shielding, which we used it to test the performance of RF transmission through various material.


Glocom Marketing Pte Ltd


Conductive glass

reference: conductive glass


Singapore Safety Glass

Conductive paint



Conductive tapes

, Singapore Network Ethernet WiFi RS232 RS485 USB I/O Controller



4. PCB Footprint reference



Click here to access to footprint page.


5. Tap drill guide (metric chart)

Matric coarse pitch

Screw Standard


diameter 'O'

Drill size

diameter 'I'


M 1 1.0mm 0.75mm  
M 1.1 1.1mm 0.85mm  
M 1.2 1.2mm 0.95mm  
M 1.4 1.4mm 1.10mm  
M 1.6 1.6mm 1.25mm  
M 1.8 1.8mm 1.45mm  
M 2 2.0mm 1.60mm  
M 2.2 2.2mm 1.75mm  
M 2.5 2.5mm 2.05mm  
M 3 3.0mm 2.50mm 0.5mm
M 3.5 3.5mm 2.90mm  
M 4 4.0mm 3.20mm 0.7mm
M 4.5 4.5mm 3.70mm  
M 5 5.0mm 4.20mm 0.8mm
M 6 6.0mm 5.00mm 1.0mm
M 7 7.0mm 6.00mm 1.0mm
M 8 8.0mm 6.70mm 1.25mm
M 9 9.0mm 7.80mm  
M 10 10.0mm 8.50mm 1.5mm
M 11 11.0mm 9.50mm  
M 12 12.0mm 10.20mm 1.75mm
M 14 14.0mm 12.00mm  
M 16 16.0mm 14.00mm  
M 18 18.0mm 15.50mm  
M 20 20.0mm 17.50mm  
M 22 22.0mm 19.50mm  
M 24 24.0mm 21.00mm  
M 27 27.0mm 24.00mm  

1/4"-36 6.5mm 6.0mm Thread for SMA RF connector thread

1/4"-36 6.5mm 6.0mm Toggle switch thread






Image of a machine cap screw

Enlarge image of the screw thread


diameter 'I'

Diameter of the screw core

(Hole size to drill, for tapping the thread )


diameter 'O' Diameter of the screw thread









  Fastener Manufacturer:


Fasterner selection guide



Plastic fastener, Cable accessories

Enclosure bumper/rubber padding






Self-Clinching Nut, Standoff Guide  

Self Clinching Standoff

Installation Guide



Self Clinching Nut

Installation Guide

Silicone Moldmaking Techniques & Materials Silicon Moldmaking techniques & material guide.pdf


Toggle Switch (chasiss mount)

toggle switch
Toggle switch dimension and thread size 1/4-40 UNS-2A
toggle switch dimension and thread size
Toggle switch drill hole size
toggle switch drill guide, Singapore Network WiFi Ethernet Solution



6. Common Connector Pin Out

This is a connector pin out reference.


3.5mm 4pins

Commonly use for:
- Earphone + Microphone


Earphone + Microphone:
Pin 1- Left Speaker
Pin 2- Right Speaker
Pin 3- Mic+
Pin 4- Ground

iPhone Mobile Phone Earpiece:
Samsung Galaxy
Samsung Nexus S
Pin 1- Left Speaker
Pin 2- Right Speaker
Pin 3- Ground, Push Switch
Pin 4- Mic+, Push Switch

Nokia Mobile Phone Earpiece:
Pin 1- Left Speaker
Pin 2- Right Speaker
Pin 3- Mic+, Push Switch
Pin 4- Ground, Push Switch

3.5mm 3pins

Commonly use for:
- Earphone
- Speaker


Earphone/Speaker pin out:
Pin 1- Left Speaker
Pin 2- Right Speaker
Pin 3- Ground

Notes: Speaker's load is inductive. Measuring the resistivity from the pins will usually yield very low resistance (near to short circuit). Measurement by probing the pin in reverse will yield the same result.

Microphone pin out:
Pin 1- Mic+
Pin 2- Mic Power
Pin 3- Ground

Earphone/Microphone pin out:
Pin 1- Spk+
Pin 2- Mic+
Pin 3- Ground

3.5mm 2pins


Commonly use for:
- Microphone


Microphone pin out:
Pin 1- Mic+
Pin 2- Ground

Notes: Commonly available electret microphone contains active components. The positive terminal of a microphone can be detected using a ohm meter. Measure Mic+ (+ve Probe), Mic- (-ve Probe) will yield a higher resistivity than probing the reverse way Mic- (+ve Probe), Mic+ (-ve Probe).

Electret microphone equivalent circuit

Other type of microphone:
- The Carbon Granule Microphone
- The Piezoelectric Microphone
- The Condenser Microphone
- The Dynamic Microphone
- The Ribbon Microphone
- The Hot-Wire Microphone



3.5mm 3pins, 2.5mm 3pins


Known to be use for:
- Walkie talkie

3.5mm 3pins, 2.5mm 2pins

Known to be use for:
- Walkie talkie

3.5mm 2pins, 2.5mm 3pins

Known to be use for:
- Walkie talkie

3.5mm 2pins, 2.5mm 2pins

Known to be use for:
- Walkie talkie

Mini DIN socket 6 pins (female receptacle)



Known to be use for:
- Walkie talkie


Walkie Talkie pin out:
Pin 1- Mic- / PTT Switch common
Pin 2- Mic+
Pin 3- PTT Switch
Pin 4- Speaker+ (left)
Pin 5- ---unused--- (right)
Pin 6- Speaker-

Mini DIN plug 6 pins (male pins)


Known to be use for:
- Walkie talkie


Walkie Talkie pin out:

Pin 1- Mic- / PTT Switch common
Pin 2- Mic+
Pin 3- PTT Switch
Pin 4- Speaker+ (left)
Pin 5- ---unused--- (right)
Pin 6- Speaker-

Pin 1 Mic- / PTT Switch common Re
Pin 2 Mic+ Bk
Pin 3 PTT Switch Wh
Pin 4 Speaker+ (left) Ye
Pin 5 ---unused--- or Speaker+ (right) Bl
Pin 6 Speaker- Gr


Mini DIN plug 4 pins (male pins)

Commonly use for:
- S-Video
- Walkie talkie PTT switch connector


Walkie Talkie pin out:
Pin 1- ---unused---
Pin 2- ---unused---
Pin 3- PTT Switch
Pin 4- PTT Switch

Mini DIN plug 4 pins (female pins)


DIN 5 pins



Known to be use for:
- Bike's audio connector


Bike Audio pin out:
Pin 1- ---unused---
Pin 2- ---unused---
Pin 3- PTT Switch
Pin 4- PTT Switch

DIN 7 pins


Known to be use for:
- Bike's audio connector


Bike Audio pin out:
Pin 7- PTT Switch (White)
Pin 3- Speaker L
Pin 5- Speaker R
Pin 2- Speaker Gnd
Pin 4- Mic-
Pin 1- Mic+
Pin 6- Mic shield

DIN 8 pins

GX16 Aviation plug and socket connectors (16mm)




FD-M16 16mm Connectors FD-M16%20connector%20selection.jpg

XLR Plug 3 pins


Commonly use for:
- Studio Microphone


Studio Microphone pin out:
Pin 1- Shield
Pin 2- Positive Balance Signal
Pin 3- Negative Balance Signal

DC barrel jack/socket

DC barrel jack (OD=5.5mm, ID=2.1mm, length=11 to 12mm)


DC barrel socket



SMA RF connector (socket for WiFi Antenna)

sma rf cablesma rf cablesma rf cable
Toggle switch dimension, drill hole dimension and thread size 1/4-40 UNS-2A
sma connector dimension




7. Name of Connectors/Plugs



UK 3 pins Plug

EU 2 pins Plug

IEC 3 pins Socket


Molex SPOX 5267 series connector header THT 2.5mm 4 way

Molex 5263 housing crimp receptacle 2.5mm 4 way

2.54mm pitch

Product Family Crimp Terminals
Series 5263
Product Name SPOX
UPC 800753534919
Gender Female
Material - Metal Phosphor Bronze
Material - Plating Mating Tin
Material - Plating Termination Tin
Net Weight 43.200/mg
Plating min - Mating 0.889μm
Plating min - Termination 0.914μm
Termination Interface: Style Crimp or Compression
Wire Insulation Diameter 1.90mm max.
Wire Size AWG 22, 24, 26, 28
Wire Size mm NA
Old Part Number 5263PBTL

molex KK 6410 series

molex KK 6471 crimp receptacle

2.54mm pitch

Product Family Crimp Terminals
Series 4809
Product Name KK
UPC 800753746022
Gender Female
Material - Metal Brass
Material - Plating Gold
Material - Plating Gold
Net Weight 0.066/g
Plating min - Mating 0.381μm
Plating min - Termination 0.381μm
Termination Interface: Style Crimp or Compression
Wire Insulation Diameter 1.57mm max.
Wire Size AWG 22, 24, 26, 28, 30
Wire Size mm NA
Old Part Number 4809555L

TJC8 connector (header and housing pins)

Pin Header PCB Crimp Style Cable Connector

TJC8 series(2.54mm pitch)Wire to Board Crimp style cable P.C.B connector housing terminal pin header

1. Pole: 1-40
2. Housing pins for wire size AWG28# - 22#
3. Header pins for PC board thickness: 1.6mm, 2.54mm pitch
4. Temperature range: -25C~85C
5: Voltage rating: 250V. AC/DC
6. Current rating: 3A
7. Contact resistance: 0.02
8. Insulation resistance: 800M
9. Withstand Voltage: 1000V. AC/1Min
10. Material:
Housing: PA66
Wafer: PBT
Terminal: Phos. Bronze Tin plated

Crimping tool, die sets size = ???

JST ZH connectors





SZH-002T-P0.5 (0.08-0.13mm2, AWG28# - 26#, OD 0.8-1.1mm)
SZH-003T-P0.5 (0.032-0.08mm2, AWG32# - 28#, OD 0.5-0.9mm)


Crimp terminal,
Insulated push-on,
Male tab (6.35mm or 1/4 inch tab connector),
Male bullet,
Female bullet

Red Insulation   0.5-1.5mm2 / 22-16 AWG
Blue Insulation  1.5-2.5mm2 / 16-14 AWG
Yellow Insulation   4.0-6.0mm2 / 12-10 AWG

Good terminal is made of copper (tinned), not aluminium.

Wire size for various ferrule size (color determine the size)





8. Name of Cable/Wire



Ribbon Cable & IDE connectors

 IDC connector pin rating is 1A.

Flat Flexible Cable (FFC)


Flex Jumper

, Singapore Network Ethernet WiFi RS232 RS485 USB I/O Controller



email:    contact->email_siongboon  




Keyword: mm inch mil thou, tap drill size, reference guide, PCB trace resistivity computation calculator, Foot print reference, Cable wire gauge resistance, cable wire selection, fastener