Tag Archives: diodes

Crosstown Traffic: KB6NU talks “1Nxxxx” and “2Nxxxx” diode and transistor part numbers.

Dan KB6NU posts interesting information from Wikipedia about how diodes and transistors got their “1Nxxxx” and “2Nxxxx” part numbers.  Turns out these numbers spawned from the old vacuum tube part numbering systems:

The early work began as a part numbering system for devices which became popular in the 1960s. The first semiconductor devices, such as the 1N23 silicon point contact diode, were still designated in the old RMA tube designation system, where the “1” stood for “No filament/heater” and the “N” stood for “crystal rectifier”. The first RMA digit thus was re-allocated from “heater power” to “p-n junction count” to form the new EIA/JEDEC EIA-370 standard; for example, the 1N4001 rectifier diode and 2N2222 transistor part numbers came from EIA-370. They are still popular today. In February, 1982, JEDEC issued JESD370B, superseding the original EIA-370 and introducing a new letter symbol “C” that denotes the die version, as opposed to “N”, now meaning the packaged version. The Japanese JIS semiconductor designation system employs a similar pattern. JEDEC later developed a numbering system for integrated circuits, but this did not gain acceptance in the semiconductor industry. The European Pro Electron semiconductor numbering system originated in a similar way from the older Mullard–Philips tube designation.

Thanks, Dan, for sharing that interesting fact!