One good example is a protective loop for a security system. The sensors on doors and windows could be a normally closed circuit in which all of the triggering devices are wired in series. If one device is tripped (creating a gap in the series circuit and thus no circuit) the alarm will sound. This kind of circuit is good because it tells you if there is a maintenance problem such as a broken wire in the circuit also.
Another example of a series circuit is older tree lights where if one bulb burned out, none of the lights would work. With the tree it is a disadvantage while an advantage with a security system.
Another example of a series circuit is older tree lights where if one bulb burned out, none of the lights would work. With the tree it is a disadvantage while an advantage with a security system.
