Circuit 2 for controlling one light in multiple places

(2) The second
    circuit of the electric light multi-ground control circuit is shown in Figure 2-28. It consists of load sensor SL,
bistable trigger A, solid state relay SSR and DC circuit
. When any button SBi ~
SB, is pressed, pin 4 of SL outputs high level, and through A and SSR, the lamp
EL lights up. When any button is pressed again,
pin 4 of SL outputs a pulse signal again, causing the circuit of A to flip
, the SSR control terminal voltage disappears, and the light EL goes out.
    SL uses I series load sensor ZA-2N; A uses
double D flip-flop C043 or CD4013 to form a bistable circuit
; solid state relay SSR should be selected according to the load size.
Generally, the rated current should be greater than 1.5 times of the load current
. The voltage should match the load voltage .