Data Sheet

-35-
45. Switches in Series and Parallel
In this circuit, if you want to light up the lamp (76), you can
turn on the switch (62), or you can place the magnet (7) near
the reed switch (83) and press the press switch (61) at the
same time.
Using a hotel analogy, the reed switch (83) could represent
a key card holder and the press switch (61) could be a light
in the room. In order for lights to turn on in the room, the
key card holder must put the key in the slot near the door
entrance AND must ip the switch on the lights. However,
employees (e.g. maids) at the hotel may have a master key card
(the switch (62)) that turns on all the lights in the room
regardless of which switches are turned on or off in the room.
46. Three-person Rocket Launch
Build the circuit as shown on the left. If you want to turn on
the two LEDs, you need to turn ON all three switches at the
same time.
In this circuit, pretend the two LEDs are a rocket. To launch
the rocket the switch (62) must be ON, AND the press switch
(61) must be ON, AND the reed switch (83) must be turned
ON with the magnet (7).
Systems like this are used to prevent accidental rocket
launching by having the switches placed far enough apart that
it requires three people to turn them on simultaneously.