From the internal circuit diagram of the NE555 you can see that the THRESHOLD input Pin 6 (THR) is connected to a comparator. The second input of the comparator is connected to the voltage divider, at which the voltage V = 2/3 Vcc = 6 V applies. The output of the comparator is connected to the RESET input of the RS latch.
![]() Internal circuit diagram THRESHOLD input NE555. |
Now consider the circuit shown...
![]() Circuit THRESHOLD input NE555. (Enlarge) |
![]() Circuit diagram THRESHOLD input NE555. |
As soon as you push the pushbutton switch S2...
But there is also another way to reset the NE555...