tony sayer wrote:



The triac crow bar is tripped by the NE555 circuit, which is
an ionisationdetector. The antenna symbol refers to a wire that
runs next to the panels and picks up RF noise generated by near
ionising conditions. The NPN transistor will then conduct and
trigger the NE555.


That transistor, no RF decoupling on it's BE junction;-?..

** The diode & coil circuit produces DC at the base of the transistor in response to strong RF energy.


Wonder how they test it in the factory prolly some spark coil gubbins;!


** More likely a small CB transmitter.


..... Phil