Electric line forming intruder deterrent - has periodically switched low voltage applied across capacitor and and transformer with output connected to exposed line

摘要

A source of supply voltage (1) is connected to a resistance (2) and the first winding of a transformer (5). The second terminal of the winding is connected back to the supply via a switch (4). A capacitor (3) is connected in parallel with the primary winding of the transformer. The secondary winding is connected by one terminal to earth (15), and by the second terminal via a line connected around a building as an electric fence. This produces periodic pulses, an actuation of the switch to deter the potential intruder. The device operates within safe limits in a fail-safe mode.