Commonly used PCB metric units

1 feet = 12 inch

1 inch = 1000 mill Mil

1mil = 25.4um

1mil = 1000uin (MIL ears sometimes become British)

1um = 40uin (some companies call micro-inches as microphones, but they are actually micro-inches)

1 oz = 28.35g/square foot = 35 microns

H = 18 microns

4mil/4mil = 0.1mm/1mm mm linewidth

1asd = 1 AMPS/square meters = 10.76 AMPS/square feet

1 AM = 1 amps min = 60 couplet is mainly used for precious metal plating such as gold plating

1 square meter = 10.76 square feet

1 ounce = 28.35 grams, in imperial units

1 gallon (English) = 4.5 litre

1 gallon US = 3.785 litre

1kha = 1000 Security hour

1 hour per ampere = 3600 Mbps

 

 

Proportion

Beaufort = 145-145/SG.

SG. Specific Gravity (grams/cubic centimeter) = 145/(145-wave beauty)

 

Original article, reprinted Please note:Reposted from http://www.mr-wu.cn/Wu chuanbin's blog

Link:PCB commonly used metric unit http://www.mr-wu.cn/pcb-conversion-of-measurement-units/

Commonly used PCB metric units