S sxy Member May 12, 2022 #1 Hi In the file attached why in case of the lower input is high and the higher input is low: we have current in the Base of T4; so why the led L1 is not glowing from the current of the Emitter of T4? Thanks Attachments XNOR CIRCUIT1.jpg 407.7 KB · Views: 249
Hi In the file attached why in case of the lower input is high and the higher input is low: we have current in the Base of T4; so why the led L1 is not glowing from the current of the Emitter of T4? Thanks
rjenkinsgb Well-Known Member Most Helpful Member May 12, 2022 #2 It looks as if it could do, until the LED gets destroyed.... It is a very badly designed circuit - with both inputs high, the power is connected to the LED with no current limit, via T3 and T4. Unless the power source is very weak, that will damage the LED.
It looks as if it could do, until the LED gets destroyed.... It is a very badly designed circuit - with both inputs high, the power is connected to the LED with no current limit, via T3 and T4. Unless the power source is very weak, that will damage the LED.