the idea of the citcuit is to prevent the passage of certain value of the current ,
for example we have a lamp ( placed in the collector of 4.7 resistor ) and we want to know if this lamp are consuming more than certain current for example 1A ,
the two resistors in the right are push pull , the principle is when one of the transistors is ON the other is OFF so one will short a led and the other with short another led , and these leds are our indicative if there our lamp consume more than 1A , if the red led light means that it consume more , if the green led light means it consume less than 1A
Remark : the circuit is designed it in the which the voltage Vbe =0.7 v
