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Resistor Color Calculator

Resistor Color Calculator
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This Resistor Color Calculator allows you to enter resistor color codes to determine their Ohm-age (value), but it also works the other way around allowing you to enter the desired Ohm-age to find out what the needed color codes for the resistor should be.

I’ve had this one on all my old websites since way back in the day … but I do find myself going there often when I’m playing with electronic projects.
At some point I figured, it could use an update and it should probably get a home at Tweaking4All as well.

The updated version can now also calculate with 5 band resistors.




Resistor Color Calculator

The Resistor Color Calculator can be used for free of course and was written in JavaScript by myself around the year 1999 or 2000.

The original was based on an old cardboard sliding card my dad used to have to determine values and colors and it has been available at WeetHet.nl for years and after a little refresh I’ve posted it here as well.

Usage: Select your color or value in the dropdown lists below and the resistor and Ohm-age calculation will change automatically.

Resistor Type:   Additional:
 
 

 

  First Ring Second Ring Third Ring 1 Multiplier Tolerance Temperature 2 Failrate 3
Colors:
Values:

 

Calculated Ohm-age:

4.7 Kilo Ω   (± 5 %)

 

First RingSecond RingThird Ring (optional)Multiplier RingTolerance RingTemperature Ring (optional)Failrate Ring (optional)

 

Notes:
1 Modern metal film resistors use an extra band to indicate it’s value, sometimes referred to as a “5 band code”.
2 The temperature (coefficient) ring is often seen with precision resistors, indicating the resistance change caused by temperature changes.
3 The reliability (or: fail rate) ring is rarely used in commercial applications, however frequently used in military applications.

 

Standard Resistor Values

Not all thinkable values are available, in part caused by the fact that all resistors have some sorts of tolerance.
For example, a 100 Ohm resistor with a tolerance of 10% can actually have an value between 90 Ohm and 110 Ohm.

This is why the IEC (International Electrotechnical Commission) create the resistance and tolerance values into a norm, and are referred to as “preferred resistor values” or E-series (standard IEC 60063).

To help you (and myself) find the best matching resistor, I created a interactive table of the defined E-series values.
The most commonly used E-series is undoubtedly the E12 series. 

In the table below; check the series you’d like to see. The red boxes indicate that the value exists in these series. The grey boxes indicate that a value exists in a series you didn’t select.
For example, when selecting just the E12 series, you’ll see right away which of the E12 series values also exist in the other series.
You can select multiple series at the same time.

Show Resistor E-Series:

Value

E192

E96

E48

E24

E12

E6

100

101

102

104

105

106

107

109

110

111

113

114

115

117

118

120

121

123

124

126

127

129

130

132

133

135

137

138

140

142

143

145

147

149

150

152

154

156

158

160

162

164

165

167

169

172

174

176

178

180

182

184

187

189

191

193

196

198

200

203

205

208

210

213

215

218

220

221

223

226

229

232

234

237

240

243

246

249

252

255

258

261

264

267

270

271

274

277

280

284

287

291

294

298

300

301

305

309

312

316

320

324

328

330

332

336

340

344

348

352

357

360

361

365

370

374

379

383

388

390

392

397

402

407

412

417

422

427

430

432

437

442

448

453

459

464

470

475

481

487

493

499

505

510

511

517

523

530

536

542

549

556

560

562

569

576

583

590

597

604

612

619

620

626

634

642

649

657

665

673

680

681

690

698

706

715

723

732

741

750

759

768

777

787

796

806

816

820

825

835

845

856

866

876

887

898

909

910

920

931

942

953

965

976

988


Tips and Tricks

When buying a Resistor Kit

When looking for a nice selection of resistors, you could get started with one of those starter kits you can buy online.
These kits typically include common values, and offer right a few resistors per value – a good start when working with electronics for sure.

However, there are a few points you’d want to pay attention to (from personal experience):

  1. Make sure the color codes remain readable.
    Quite a few China packages include resistors with a lot of color rings, and sometimes it is unclear where to start reading the colors.
    Additionally, some of these have rings that are printed on them rather sloppy, making it a pain to figure out what their actual value is.
  2. Make sure at least the E12 Series values are included, preferably also the E24 series for larger sets.
  3. Resistor with a tolerance of 5%, 10% or 20% are much easier to read – you do not always need resistors with lower tolerances.
    Some of these kits come with resistors with lower tolerances. This can be great, but keep in mind that most beginning hobbyists will not very often need resistors with such a low tolerance.
    However: the low tolerance resistors can be a pain to read their values since the last ring isn’t silver or gold.
    So before selecting a kit with high tolerance: make sure you really need it (and if you’re not sure: it is very likely that you will not need those!).
Make sure you read the colors in the right order!

Usually a resistor has either a silver or a gold band at the END.
Keep that one to the right (as seen above). You’re now looking at the proper color code order (from left to right).

Measuring Resistor

Sometimes, specially with damaged or dirty equipment, color codes can be very hard to read.
I recommend using a regular multimeter (Ohm-meter) to measure the resistance (if the resistor is not completely toast).

Note: Keep in mind to not hold your fingers on the contacts of the multimeter testers or the leads of the resistor, otherwise you’re putting yourself in parallel with the resistor and the multimeter will most likely indicate a faulty value!

Note: Do not try to measure resistors in-circuit, as the result will most likely be influenced by the other components in the circuit and therefore resulting in a wrong vale …

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Comments


There are 4 comments. You can read them below.
You can post your own comments by using the form below, or reply to existing comments by using the "Reply" button.

  • Nov 8, 2014 - 5:52 AM Comment Link
    PingBack: piecesofpi.co.uk

    […] Details of the resistor colour code can be found here, and there is a useful calculator here. […]

  • Apr 22, 2017 - 12:16 AM - Mariel Comment Link

    I’ve liked this program very much. Are you selling this program?  I’d like to use this program on my website here in Brazil. Thank You very much. 

    Reply

    Mariel

  • Feb 9, 2020 - 8:51 AM Comment Link
    PingBack: www.tweaking4all.com

    […] You can use our resistor calculator (this table will be visible there as well) to determine the value of a resistor or the needed color […]



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