Resistor Finder

Finds the nearest resistor to a desired value from the standard "E" families. Resistors are commonly available from 10Ω to 1MΩ, values above and below this range are harder to find. Resistors are readily available as metal film chip resistors in surface mount packages (402, 603, 805, 1206) and leaded axial packages. These parts have fractional power capability. Resistors with larger power capability are less readily available. Ceramic capacitors in 5% and 10% tolerance follow the E24 and E12 rules. They are commonly available from 10pF to 1u. It can be prudent to stick to the E12 values: 1, 1.2, 1.5, 1.8, 2.2, 2.7, 3.3, 3.9, 4.7, 5.6, 6.8, and 8.2 when selecting capacitors.

We are in the process of redesigning our calculators. The Resistor Finder is coming soon. Check back with us!

Resistor Divider

Select the variable you wish to find, fill in the other values, and click "Calculate".

We are in the process of redesigning our calculators. The Resistor Divider calculator is coming soon. Check back with us!

Resistors in Parallel

Select the variable you wish to find, fill in the other values, and click "Calculate".

We are in the process of redesigning our calculators. Resistors in Parallel is coming soon. Check back with us!

RC Time Constant

This applet finds the time constant and corner frequency for a simple RC circuit.

We are in the process of redesigning our calculators. The RC Time Constant calculator is coming soon. Check back with us!
Family
Desired
Low Choice Error
High Choice Error
Vin
Vout
R1
R2
R1 || R2
R1
R2
R
C
Time Constant
Corner

SMD Size Vs. Power Dissipation Chart

This is a guideline chart for picking the right size SMD resistor for power dissipation.

Size
Size Metric
Length (in)
Width (in)
Length (mm)
Width (mm)
Height (mm)
Watts
Max Operating Voltage (V)
No Margin Resistance for 3.3V Power Dissipation (0hms)
0201
0603
0.02
0.01
0.60
0.30
0.25
0.05
25
218
0402
1005
0.04
0.02
1.00
.5
0.35
0.06
50
182
0603
1608
0.06
0.03
1.55
0.80
0.50
0.1
75
109
0805
2012
0.08
0.05
2.00
1.25
0.50
0.125
150
87
1206
3216
0.12
0.06
3.20
1.60
0.60
0.25
200
44
1210
3225
0.12
0.10
3.20
2.60
0.50
0.5
200
22
1218
3246
0.12
0.18
3.10
4.60
0.90
1.0
200
11
2010
5025
0.20
0.10
5.00
2.60
0.70
0.75
200
15
2512
6432
0.25
0.12
6.30
3.20
0.60
1.0
250
11
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