Schematic Diagram Symbols
• Wires
Wires are connected with a dot at the junction. Wires that are not connected simply cross without
a connection dot. If wires form a cross at their connection, it is better to stagger them forming ”t”
junctions so that the connection is clear even if the connection dot is not.
S
S?
1
wires crossing but
not connected
preferred, to
prevent ambiguity
wires connected
at center point
1
2
pushbutton
switch
archaic − don’t use
n.
single pole
normally c
S?
v3.3
Figure 1: Wires
earth ground
• Power and
v5.0
1
signal ground
2
pushbutton
1
switch
R?
power supply
power supply
connection
connection
Groundwires
Symbols
preferred, to
crossing but
wires connected
to +5 volts
to +3.3 volts
prevent ambiguity
not connected
at center point
archaic − don’t use
10k
10K
Variable res
called a pote
Resistor
v3.3
D?
Z?
earth ground
D?
2
v5.0
D?
signal ground
R?
power supply
power supply
connection
connection
to +5 volts
to +3.3 volts
5.6V
1N5711
FigureLight
2: Power
Symbols
Emitting and
DiodeGround
(LED)
Zener diode, Usually has
Schottky diode
rated voltage shown
1N4148
10k
Standard Diode
Resistor
There are several symbols usedZ?
for ground. Some conventions
distinguish
signal
D?
D?earth ground,D?
ground, and chassis ground. However, these are often used interchangeably. Many different
C? upon the country
C?
power symbols are
of origin. The actual supply voltage
C? also seen depending
usually indicated.
5.6V
1N4148
1N5711
I?
1uFhas Light Emitting Diode (LED)
Zener diode, Usually
1mA
Schottky diode
Standard Diode
• Switches 100pf
0.1uF
rated voltage shown
polarized electrolytic
capacitor
kindsoroftantalum
switches
seen
variable capacitor
There are many different
C?
C?
M?
M
preferred, to
event ambiguity
archaic − don’t use
Motor
S?
B?
1 100pf
2
3V
S?
TP? 1uF
n.c.
Independent Current Source
Most will resemble these samples.
C?
C
S?
n.o.
netname
1 0.1uF
2
1
2
non−polarized
polarized electrolytic
variable capacitor
capacitor
or
tantalum
capacitor
pushbutton
single pole single throw single pole
single throw
Battery
Test Point
Connector
switch
normally closed switch
normally open switch
M
R?
power supply
connection
to +5 volts
Motor
10k
Resistor
D?
Independent Vo
C
Q?
I?
B
Q?
1mA
2N4403
Independent
Current
E
E Source
Photo transistor
M?
v5.0
D?
non−polarized
capacitor
in schematics.
PNP transistor
C
TP?
B?
Figure
3: Switches
3V
2 R?
1
3 1
Battery
Test Point
C
Q?
netname
B
2
R?
E
E
Connector
Photo transistor
10K
Variable resistor, also
called a potentiometer
In
10k
Photo resistor, its value is
nominal and varies with light
PNP tran
S?
S?
1
• Resistors
1
2
pushbutton
preferred, to
event ambiguity
S?
n.c.
1
2
single pole single throw
n.o.
2
single pole single throw
Resistors
typically do notswitch
have a rated
wattage shown. In
most schematics, the resistors are all of
normally closed switch
normally open switch
archaic − don’t use
the same wattage and this will be stated somewhere on the schematic.
v5.0
2
R?
power supply
connection
to +5 volts
1
10k
Variable resistor, also
called a potentiometer
1N5711
Schottky diode
preferred, to
prevent ambiguity
wires connected
at center point
v3.3
Standard Diode
earth ground
1
2
pushbutton
switch
archaic − don’t use
Figure 4: Resistors
1N4148
• Diodes
1
Photo resistor, its value is
nominal and varies with light
D?
wires crossing but
not connected
S?
S?
10K
Resistor
ED)
3
10k
D?
R?
R?
0.1uF
n−polarized
apacitor
3
v5.0
Inductor
V?
D? 10V
Independent Current Source
netname
Connector
Photo transistor
Q?
2N4403
B
E
1N5711
variable capacitor
E
C?
Schottky diode
Q?
2N4401
Figure 5: EC?
Diodes
10K
1N4148
Q? Standard Diode
Q?
PNP transistor
NPN transistor
N−channel MOSFET
0.1uF
polarized electrolytic
or tantalum capacitor
non−polarized
capacitor
BS250
P−channel MOSFET
I?
1mA
Independent Current Source
C
TP?
B?
3V
Q?
netname
Independent Voltage
Q?
2N4403
B
TITLE
Battery
FILE:
Connector
Test Point
PAGE
2
V?
10V
C
E
Motor
3
D?
2N7000
M?
M
1
B
1uF
100pf
R?
Independent Voltage Source
5.6V
Q?
2
Variable resistor
called a potentio
Resistor
Transformer
D?
Light Emitting Diode (LED)
C
C
Zener diode,
Usually has C
rated voltage shown
C?
single pole sing
normally closed
signal ground
I?
1mA
Z?
2
T?
1
R?
power supply L?
power supply
There are many types of diodes. Hereconnection
are a few of the
most common. Zener diodes will often have
connection
2
4
+5 volts
to +3.3 volts
both a part number and the rated voltage
to aid in to
understanding
4.7uHthe circuit operation.
10k
C?
n.c.
B
E
REVISION:
Photo transistor
OF
PNP transistor
DRAWN BY:
NPN
switch
normally closed switch
1
10k
Resistor
R?
R?
2
R?
normally open switch
3
• Inductors and Transformers
10K
Transformers
oftenalso
will have a small
Variable resistor,
10k dot placed at one end of its windings. These are phasing dots
Photo resistor,
its valuepolarity
is
called
a potentiometer
which
indicate
the instantaneous
voltage
at each of the ”dotted” ends of the windings is
nominal and varies with light
the same.
T?
wires connected
1
at center point
wires crossing but
not connected
48
Diode
v3.3
L?
earth ground
signal ground
t Current Source
C
B
v3.3
R?
power
supply
4
connection
to +5 volts
10k
S?
S?
n.c.
Figure
1 6: Inductors
1
2
2
D?
Z?
D?
1
n.o.
Resistor
2
D?
pushbutton
single pole single throw single pole single throw
C
preferred, to
switch
normallyQ?
closed switch
normally open switch
archaic − don’t use
Q?
5.6V
1N4148
1N5711
prevent
ambiguity
B
Light Emitting Diode (LED)
Q?
Q? Zener
Capacitors
will sometimes
have
a voltage
diode,
Usually haslisted if it is critical. Often, all the capacitors on a
Schottky diode
Standard Diode
2N4403 will have 2N4401
schematic
the same
voltage
rated
voltage rating.
shown If so, this will be stated somewhere on the schematic.
2N7000
BS250
v5.0
E
E
• Capacitors
d
power supply
power supply
transistor
PNP transistor
NPN transistor
connection
connection
to +5 volts
to +3.3 volts
D?
R?
2 R?
MOSFET
C? P−channel
C?
1
3
R?
N−channel MOSFET
C?
10k
1uF
10K
Variable resistor, also
Resistor
0.1uF
called
non−polarized
polarized electrolytic a potentiometer
100pf
D?
variable capacitor
D?
or tantalum capacitor
capacitor
Figure 7: Capacitors
M?
1N4148
Light Emitting Diode (LED)
TP?
TITLE
B?
M
Schottky diode
Standard
Diode
• Independent Sources
3V
FILE:
I?
1mA
10k
Photo resistor, its value is
Independent
nominal and varies
with light Current Source
C?
OF
Battery
Test Point
I?
1mA
0.1uF
non−polarized
capacitor
Q?
netname
E
Test Point
Connector
Photo transistor
C
B
2
REVISION:
DRAWN BY:
Connector
L?
E
E
2
Photo transistor
Inductor
PNP tran
Transformer
Independent Voltage Source
C
C
Figure
8: Independent
Sources
TP?
Q?
netname
V?
10V
Independent Current Source
In
1
4.7uH
1uF
rized electrolytic
ntalum capacitor
ttery
PAGE
Motor
T?
C
1N5711
C?
2
pushbutton
switch
archaic − don’t use
S?
Independent Voltage Source
C
es connected
center Q?
point
E
Inductor
V?
10V
1
v5.0
power supply
2
connection
Transformer
to +3.3
volts
4.7uH
I?
1mA
preferred, to
3
prevent ambiguity
S?
Q?
2N4403
B
E
3 transistor
PNP
C
Q?
Q?
Q?
2N4401
B
E
NPN transistor
2N7000
N−channel MOSFET
BS2
P−channel MOS
L?
?
C?
2
R?
1
I?
1mA
0.1uF
•
Bipolar
Junction
Transistors
(BJT’s)
10k
10K
non−polarized
electrolytic
Independent Current
Variable resistor, also
10k Source
capacitor
m capacitor Resistor
1uF
Test Point
S?
C
Q? T?
2N4403
1
B
wires crossing but
E
not connected
Connector
B
Q?
2N4401
3
preferred, to
E
prevent ambiguity
wires connected
E
at center point
• Metal
nt Current Source
PNP transistor
NPN transistor
v3.3
v5.0
2
4
4.7uH
earth groundFigure
signal
9:ground
Bipolar power
Junction
Transistors
power supply
supply
Inductor
Transformerconnection
connection
V?
10V
to +5 volts
to +3.3 volts
Oxide Field Effect Transistors (MOSFET’S)
C
Q?
E
transistor
P−channel MOSFET
N−channel MOSFET
R?
10k
E
B
D?
D?
D?
TITLE
Q?
Q?
FILE:
Q?
5.6V
1N5711
Light Emitting Diode (LED)
2N4401
PAGE
Zener diode, Usually has
Schottky
diode
2N7000
BS250
E
rated voltage shown
PNP transistor
V
c
Resistor
C
Q?
2N4403
B
2
Q?
pushbutton
s
switch
BS250
archaic2N7000
− don’t use
Independent Voltage Source
Z?
C
1
Q?
Photo transistor
L?
I?
1mA
Transformer
Independent Voltage Source
C
Q?
netname
d Diode
4
Photo resistor, its value is
nominal and varies with light
C
148
Inductor
V?
10V
3
called a potentiometer
TP?
2
4.7uH
R?
R?
NPN transistor
N−channel MOSFET
polarized electrolytic
or tantalum capacitor
non−polarized
capacitor
M?
TITLE
FILE:
M
PAGE
OF
Standard Diode
DR
P−channel MOSFET
C?
C?
C?
Figure 10: Metal Oxide Field Effect Transistors (MOSFET’S)
1uF
0.1uF
100pf
• Battery, Motor, Connections
variable capacitor
RE
1N4148
I?
1mA
Independent Current Source
C
B?
3V
TP?
OF
C
Q?
REVISION:
netname
Q?
2N4
B
DRAWN BY:
E
Motor
Indep
Battery
Test Point
Photo transistor
Figure 11: Motor, Battery and Connection Symbols
4
E
Connector
PNP transis