TRIGGER HOUSING - (LUCITE) = | PHOTOTUBE —__ i . == TUBE 3 MOUNTING PLATE “2 a Set e 4 Hi ibe? PHOTOCELI. —__| PHOTOCELL : MOUNTING BRACKET she wet L_| DIFFERENTIAL FALL-OUT COLLECTOR TRIGGER UNIT Fig. 3.3—~Light-actuated trigger mechanism. 22 TFe tm Or Ue tee MN aes CANOPY—.