High voltage detector

Simple high voltage detector based on JFET.

Used JFET: KP103I made in USSR:
KP103 transistor
Transistor can be tested with multimeter - its channel resistance is ~700 ohm and it increases to few kOhms and more in electric field (eg. near the mains cord).

High voltage detector schematic

Due to simplicity detector can be soldered directly on 6F22 battery socket:
High voltage detector

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