The Zener diode is included to protect the ULN2803 against possible damage due to "back emf" voltage spikes that may be produced when relays and motors are used.
Tzn. kdybys tam misto sedmisegmentovky mel treba krokovej motorek (tachec? vrrrrm :-)), tak je ta zenerka na to, aby odrusila zpetny proudy, vznikajici indukci v tom motorku.
|