Different Switches
Instead of mechanical switches, we can also use electronic switches:
A normally open (n.o.) switch is closed when pressed.
A normally close (n.c.) switch is open when pressed
Example of setting up a LED and a switch
U
A
B
21 3 F
GND
GND
R
R
F=1 LED on
F=0 LED off
Vcc
Switch open F=1
Switch closed F=0
Note: Typically R=1 k Ω is used.
N
-
V
+
When Current Flows the
Relay opens
Spring
contact
Relay as n.c.
Gate
Source
Drain
Base
Emitter
Collector
PMOS FET as n.c.
Négative Channel Métal
Oxide Semiconductor
Field Effect Transistor
PNP BJT as n.c.
Bipolar Junction
Transistors
N
-
V
+
When Current Flows the Relay
closes
Spring
contact
Relay as n.o.
NMOS FET as n.o.
Positive Channel Metal Oxide
Semiconductor
Field Effect Transistor
NPN BJT as n.o.
Bipolar Junction Transistors
Gate
Drain
Source
Base
Collector
Emitter