this popular circuit is called latch because it retains the output until we reset the input
explanation of the circuit :
- the concept is there are two transistors NPN and PNP
- The PNP will be ON when the NPN is ON, and its base is linked with the collector of the NPN because when the NPN is in saturation mode it works as wire btw the collector and emitter which we mean we link the collector with the ground (0V) and the PNP need it in its base to be saturated
- the concept of the buttons is ON OFF
* The first button linked btw the 9V
and NPN base is ON basically, it
gives positive voltage to the NPN
base to be on.
* The second button linked btw the
ground and NPN base is OFF
basically, it makes the base 0V and
the NPN turns off.
