MEWS: Marine Electronics Wiki

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====== Circuit Protection ======

===== Transistor as avalanche diode =====

Used in multimeters.

2SC3326 - transistor with high Vebo (25V) - used by fluke?

Fluke 17B uses BAV199 ("Low-leakage double diode").

Fluke 77III uses MMBT3904.

[[https://www.lcsc.com/datasheet/lcsc_datasheet_2209051100_TOSHIBA-2SC3326-B-LF-T_C27829.pdf|2SC3326 datasheet]]

===== PCB Spark Gaps =====

  * Remove solder mask.
  * Blunt maybe better than pointy, because the point breaks down / melts and tracks carbonise. Blunt spreads it out.
  * Can calculate a rough guestimate for voltage / gap width.
  * It will be over 1000V normally / probably.

===== Gas Discharge Tubes =====

Minimum looks like about 55V, minium available upper limit for spark starting more like 85V.

===== Lightning =====

What is needed / useful to protect NMEA 2000 network from nearby lightning strikes, or even direct ones?


http://ww1.microchip.com/downloads/en/DeviceDoc/EMC%20Newsletter%20Issue%205.pdf
https://www.eevblog.com/forum/beginners/what-is-a-spark-gap-and-why-we-need-it-on-a-pcb/