Blue Point
Engineering
Instruction
I
www.BPEsolutions.com
Pointing the Way to Solutions!
LED's Series / Parallel Setup
Battery - OR - Power Supply
12 VDC = 470 Ohm Resistor
9V DC = 330 Ohm Resistor
5V DC = Not Enough Voltage
LED's in Series
resistor
LED's = 3.3 V
20 mA
Positive
(+)
Battery - OR Power Supply
Negative
(-)
Long
Anode
+
Short
Cathode
-
LED
3.3 VDC = (Vf)
20 mA = (Current)
LED x2
Battery - OR - Power Supply
12 VDC = 330 Ohm Resistor
9V DC = 150 Ohm Resistor
5-6 V DC = 100 Ohm Resistor
Single LED
resistor
Positive
(+)
Battery - OR Power Supply
Negative
(-)
R
+
LED = 3.3 V
20 mA
A
LED
K
A
LED
K
A
Circuit
LED
-
K
Copyright © 2009 Blue Point Engineering , All Rights Reserved
Custom Equipment, Unique Electronic Products
Blue Point Engineering
Phone (303) 651-3794
www.BPEsolutions.com
Blue Point
Engineering
Instruction
I
www.BPEsolutions.com
Pointing the Way to Solutions!
LED's Series / Parallel Setup
Battery - OR - Power Supply
LED's in Parallel
12 VDC
9V DC
6V DC
5V DC
Positive
resistor
=
=
=
=
220 Ohm
150 Ohm
68 Ohm
47 Ohm
Resistor
Resistor
Resistor
Resistor
(+)
LED's = 3.3 V
20 mA
Battery - OR Power Supply
Negative
(-)
+
A
A
A
K
K
K
Circuit
LED
LED x2
LED
Battery - OR - Power Supply
24 VDC
12 VDC
9V DC
6V DC
5V DC
4V DC
resistor
LED
LED's = 3.3 V
20 mA
=
=
=
=
=
=
270 Ohm
120 Ohm
82 Ohm
68 Ohm
22 Ohm
10 Ohm
Resistor
Resistor
Resistor
Resistor
Resistor
Resistor
Positive
(+)
Battery - OR Power Supply
Negative
(-)
LED x4
Copyright © 2009 Blue Point Engineering ,
All Rights Reserved
Custom Equipment, Unique Electronic Products
Blue Point Engineering
Phone (303) 651-3794
www.BPEsolutions.com
Blue Point
Engineering
Instruction
I
www.BPEsolutions.com
Pointing the Way to Solutions!
LED's Series / Parallel Setup
+
LED's in Parallel
*
R
Best Setup
Circuit
R
R
A
A
K
LED
A
K
LED
K
LED
Battery - OR - Power Supply
24 VDC
12 VDC
9V DC
6V DC
5V DC
4V DC
=
=
=
=
=
=
270 Ohm
120 Ohm
82 Ohm
68 Ohm
22 Ohm
10 Ohm
Battery - OR Power Supply
Positive
(+)
LED x4
resistor
resistor
resistor
resistor
*
Resistor
Resistor
Resistor
Resistor
Resistor
Resistor
Negative
(-)
*
Best Setup
More LED's can be operated
with less Voltage Required.
Each LED is Protected.
LED's = 3.3 V
20 mA
Copyright © 2009 Blue Point Engineering , All Rights Reserved
Custom Equipment, Unique Electronic Products
Blue Point Engineering
Phone (303) 651-3794
www.BPEsolutions.com
Blue Point
Engineering Inc.
Instruction
www.BPEsolutions.com
LED Information
Voltage
Drop Vf
3.3 Vdc
3.1 vdc
3.3 vdc
2.25 Vdc
1.9 Vdc
LED
White
Blue
Green
Red
Yellow
I
Controller
Foward
Current mA
20 mA
20 mA
20 mA
20 mA
20 mA
LED Intensity
Level mcd
8000 mcd
6000 mcd
4000 mcd
8000 mcd
3000 mcd
Check with LED manufacture to determine actual Vf, mA, values
To calculate resistance. Ohms law is V=IR. Solving for R yields R=V/I
V is voltage in volts, I is current in amps, and R is resistance in Ohms.
V is the difference between the supplied voltage and the required voltage.
Since we're using milliamps instead of amps, we need a multiplication factor of 1000.
Since we're using the difference in supplied voltage and required LED voltage we need to
subtract. The formula becomes R = (9 volts - LED voltage required) / (current in milliamps) *
1000
Once you've calculated the resistance, you will use the closest resistor value you can find.
Example: White LED = 3.3 Vf
30mA
Power Supply- 9Vdc
9Vdc - 3.3Vdc / 20mA x 1000 = 285
Resistor Needed = 330 Ohm 1/4 Watt
( Nearest Resistor Value (330) Orange/Orange/Brown/Gold )
Calculated resistance value = 285 Ohms
Next standard 10% resistor = 330 Ohm
Power dissipated in LED = 0.114 Watts
Power dissipated in resistor = 0.19 Watts
Each LED should have it's own current
limiting series resistor if possible.
Resistor
Flat side on
Cathode side
Cathode
(K)
(-) Negative
Connection
Long Lead
(+)
Short Lead
LED
Short Lead
(-)
Long Lead
(+)
Flat side on
Cathode side
(+) Positive
Connection
Anode
Clear LED
Color LED
(A)
Colors- Red, Green, Colors- Red, Green, Blue,
Blue, Yellow, White
Yellow, White, Orange
Custom Equipment, Unique Electronic Products
Phone (303) 651-3794
Blue Point Engineering Inc.
www.BPEsolutions.com