µRuler Legend v1.0

oz | | µm |

ounce | | micrometer/micron |

**Ounce to Micron conversion table for PCB copper thickness.**

SMD FOOTPRINTS | | POW |

new + (old) SMD sizes in mm | | Resistor Power |

**Size (in mm) of various SMD components plus the general power of resistors in that size.**

mil | | --> | | mm | | [Conversion Formulas] |

thousandth of an inch | | to | | millimeters | | mm to in/mil & vice versa |

**Table of mil to/from mm conversions plus formulas.**

V | | INT | | MASK | | BARE | | >3km |

volts | | internal PCB layer | | top PCB layer *with* mask | | top PCB layer *without* mask | | at altitudes above 3km |

**This table shows minimum PCB trace separation (in mils) for various voltages and locations.**

mils | | A/10° | | A/5° | | A/1° | | mR/in |

trace width | | 10°C above ambient | | 5°C above ambient | | 1°C above ambient | | milliohms per inch |

**Maximum current for various trace widths (0.5oz copper) at several temperatures (°C) above ambient.**

mils | | A/10° | | A/5° | | A/1° | | mR/in |

trace width | | 10°C above ambient | | 5°C above ambient | | 1°C above ambient | | milliohms per inch |

**Maximum current for various trace widths (1oz copper) at several temperatures (°C) above ambient.**

mm | | 1°C | | 5°C | | 10°C |

via size | | 1°C above ambient | | 5°C above ambient | | 10°C above ambient |

**Max current for various diameter 1mil thick vias at several temperatures above ambient.**

SQ PIN | | DIAmm |

header size | | equivalent diameter hole |

**Correct diameter hole needed for corresponding (square) pin size.**

capacitor number | | capacitor letter | | size in mm |

**Size (in mm) of SMD Tantalum Capacitors.**