Circuitry 101: How to Hook Up LEDs

Below we've created a very basic guide to help people unfamiliar with circuits get their LEDs up and running without blowing them out and wasting all their money. IT IS VERY BASIC!! Current is hardly ever mentioned, not because it's not important, but because we've found it makes things confusing when trying to teach people about this sort of thing. If we've done a bad job explaining things or if you have a question this doesn't answer, use the contact form at the bottom of this page to let us know what's up.

There's two basic types of circuits: Series and Parallel.

Series or "How do I power lots of LEDs off a higher voltage source?"

When LEDs are placed in a series, the voltage is dispersed between the LEDs, meaning less voltage goes to each LED. This can be very useful. For example, if a 12 volt adapter were powering one LED, there'd be 12V going through that LED which is way too much for any LED to handle and would result in a rather unpleasant burning smell.

However, if you take that same 12V power source and put 4 LEDs in series, there would be 3V going to each LED and (assuming the LEDs are made to run off 3V) each would be powered and just dandy. Check out this illustration:

It's important to notice how the LEDs are positioned: (-) (+), (-) (+), etc. making sure that the end (-) connects to the (-) wire and the end (+) connects to the (+) wire, if any LEDs are backwards nothing bad will happen, they just won't turn on.

If three LEDs were in series with a 12V source, each would receive 4V, if six were in series, each would receive 2V, etc.

"But what if I have four LEDs powered from a 12V source and I want each to receive less than than 3V/ea?" This is where the little 'Resistor(s)' squiggly comes in. By adding a resistor it's possible to tone down the amount of voltage each receives. To find out what value resistor you should use, use an led calculator such as this one . Go to the middle form where it says 'LEDs in series' and simply type in your power sources' voltage, the LEDs' voltage you'd like and the LEDs current capability (use 20mA.) It then tells you what ohmage resistor to stick in the circuit.

1 Foot = 0.305 meters
1 Meter = 3.281 feet
1 Meter = 39.37 inches
1 Square Meter = 10.76 sq. Feet
 

1 U.S. Gallon of Water
1 Cu. Foot of Water
1 Imperial Gallon
1 Liter
 

8.3357 Pounds
62.3554 Pounds
10.0 Pounds
2.2 Pounds
 

1 Atmosphere
1 Atmosphere
1 Pound per Square Inch
1 Pound per Square Inch
1 Foot of Head
1 Inch of Water Column
1 Kilogram/sq. Centimeter
1 Foot of Water
 

33.94 Ft. of Water @ 62°F
14.6963 lbs./sq. Inch
2.31 Feet of Head
27.7612 Inches of Water
.433 Pounds/sq. Inch
.0360 Pounds/sq. Inch
14.22 lbs./sq. Inch
62.3554 lbs./sq. Foot
 

1 Gallon/Minute (U.S.)
1 Gallon/Minute (U.S.)
1 Gallon/Minute (U.S.)
1 Gallon/Minute (U.S.)
1 Gallon/Minute (U.S.)
1 Gallon/Minute (U.S.)
1 Cubic Ft. per Second
1 Liter per Second
1 Acre Inch per Hour
1 Acre Foot per Day
1,000,000 Gallons per Day
1 Cubic Ft. per Second
 

.002228 cu. ft./Second
.13368 cu. ft./Minute
8.0208 cu. ft./Hour
.06309 Liters/Second
3.78533 Liters/Minute
.0044192 Acre Ft./24 Hrs.
448.83 GPM
15.85 GPM
452.57 GPM
226.3 GPM
694.4 GPM
.992 Acre Inches/Hr.
 

1728 Cubic Inches
231 Cubic Inches
27 Cubic Feet
1 Cubic Foot
1 Cubic Yard
16 Drams
32 Ounces
4 Quarts
1 Gallon
1 Gallon
1 Gallon
27.154 Gallons
325,851 Gallons
1,000,000 Gallons
1 Acre Foot
Volume of a Cube
Volume of a Pyramid
Volume of a Sphere
 

1 Cubic Foot
1 Gallon
1 Cubic Yard
7.48052 Gallons (U.S.)
202 Gallons (U.S.)
1 Ounce
1 Quart
1 Gallon
3.785 Liters
.00379 Cubic Meters
.833 Imperial Gallon
1 Acre Inch
1 Acre Foot
3.0689 Acre Feet
43,560 Cubic Feet
Area of Base x Height
1/3 Area of Base x Height
Diameter Cubed x .5236
 

Horse Power

GPM x Total Head (Ft.)
3960 x Pump Efficiency

Pump Efficiency

GPM x Total Head (Ft.)
3960 x BHP to Pump

1 Horse Power
1 Horse Power
1 Horse Power
 

33,000 Ft. Pounds/Minute
746 Watts
.746 Kilowatts
 

Weight of 100' of pipe filled with water

Size (Nom)

@ 3.0'/Second

@ 3.5'/Second

1/64

0.0156

0.3969

1 1/64

1.0156

25.7969

2 1/64

2.0156

51.1969

1/32

0.0313

0.7938

1 1/32

1.0313

26.1938

2 1/32

2.0313

51.5938

3/64

0.0469

1.1906

1 3/64

1.0469

26.5906

2 3/64

2.0469

51.9906

1/16

0.0625

1.5875

1 1/16

1.0625

26.9875

2 1/16

2.0625

52.3875

5/64

0.0781

1.9844

1 5/64

1.0781

27.3844

2 5/64

2.0781

52.7844

3/32

0.0938

2.3813

1 3/32

1.0938

27.7813

2 3/32

2.0938

53.1813

7/64

0.1094

2.7781

1 7/64

1.1094

28.1781

2 7/64

2.1094

53.5781

1/8

0.1250

3.1750

1 1/8

1.1250

28.5750

2 1/8

2.1250

53.9750

9/64

0.1406

3.5719

1 9/64

1.1406

28.9719

2 9/64

2.1406

54.3719

5/32

0.1563

3.9688

1 5/32

1.1563

29.3688

2 5/32

2.1563

54.7688

11/64

0.1719

4.3656

1 11/64

1.1719

29.7656

2 11/64

2.1719

55.1656

3/16

0.1875

4.7625

1 3/16

1.1875

30.1625

2 3/16

2.1875

55.5625

13/64

0.2031

5.1594

1 13/64

1.2031

30.5594

2 13/64

2.2031

55.9594

7/32

0.2188

5.5563

1 7/32

1.2188

30.9563

2 7/32

2.2188

56.3563

15/64

0.2344

5.9531

1 15/64

1.2344

31.3531

2 15/64

2.2344

56.7531

1/4

0.2500

6.3500

1 1/4

1.2500

31.7500

2 1/4

2.2500

57.1500

17/64

0.2656

6.7469

1 17/64

1.2656

32.1469

2 17/64

2.2656

57.5469

9/32

0.2813

7.1438

1 9/32

1.2813

32.5438

2 9/32

2.2813

57.9438

19/64

0.2969

7.5406

1 19/64

1.2969

32.9406

2 19/64

2.2969

58.3406

5/16

0.3125

7.9375

1 5/16

1.3125

33.3375

2 5/16

2.3125

58.7375

21/64

0.3281

8.3344

1 21/64

1.3281

33.7344

2 21/64

2.3281

59.1344

11/32

0.3438

8.7313

1 11/32

1.3438

34.1313

2 11/32

2.3438

59.5313

23/64

0.3594

9.1281

1 23/64

1.3594

34.5281

2 23/64

2.3594

59.9281

3/8

0.3750

9.5250

1 3/8

1.3750

34.9250

2 3/8

2.3750

60.3250

25/64

0.3906

9.9219

1 25/64

1.3906

35.3219

2 25/64

2.3906

60.7219

13/32

0.4063

10.3188

1 13/32

1.4063

35.7188

2 13/32

2.4063

61.1188

27/64

0.4219

10.7156

1 27/64

1.4219

36.1156

2 27/64

2.4219

61.5156

7/16

0.4375

11.1125

1 7/16

1.4375

36.5125

2 7/16

2.4375

61.9125

29/64

0.4531

11.5094

1 29/64

1.4531

36.9094

2 29/64

2.4531

62.3094

15/32

0.4688

11.9063

1 15/32

1.4688

37.3063

2 15/32

2.4688

62.7063

31/64

0.4844

12.3031

1 31/64

1.4844

37.7031

2 31/64

2.4844

63.1031

1/2

0.5000

12.7000

1 1/2

1.5000

38.1000

2 1/2

2.5000

63.5000

33/64

0.5156

13.0969

1 33/64

1.5156

38.4969

2 33/64

2.5156

63.8969

17/32

0.5313

13.4938

1 17/32

1.5313

38.8938

2 17/32

2.5313

64.2938

35/64

0.5469

13.8906

1 35/64

1.5469

39.2906

2 35/64

2.5469

64.6906

9/16

0.5625

14.2875

1 9/16

1.5625

39.6875

2 9/16

2.5625

65.0875

37/64

0.5781

14.6844

1 37/64

1.5781

40.0844

2 37/64

2.5781

65.4844

19/32

0.5938

15.0813

1 19/32

1.5938

40.4813

2 19/32

2.5938

65.8813

39/64

0.6094

15.4781

1 39/64

1.6094

40.8781

2 39/64

2.6094

66.2781

5/8

0.6250

15.8750

1 5/8

1.6250

41.2750

2 5/8

2.6250

66.6750

41/64

0.6406

16.2719

1 41/64

1.6406

41.6719

2 41/64

2.6406

67.0719

21/32

0.6563

16.6688

1 21/32

1.6563

42.0688