Resistor Color Code Flashcards: 4 Bands, 5 Bands & Tolerance
Practise 42 original resistor color-code prompts: decode and build conventional 4- and 5-band codes, calculate nominal tolerance intervals, and repair common errors.
About this deck
Read the band roles before doing the arithmetic. These 42 resistor color code flashcards use written color names to practise conventional four- and five-band resistor markings.
You’ll retrieve band roles and selected color values, decode codes into nominal resistance and tolerance, and build codes from an explicit band count, nominal value and tolerance. Reverse encoding is a separate card task because it needs recall in the other direction. Short calculations cover ohms, kiloohms and megaohms; nominal tolerance intervals; exact hypothetical boundary checks; and local repairs for wrong roles, zero digits, units and premature rounding.
All ten significant-digit colors and all conventional multipliers, including gold ×0.1 and silver ×0.01, appear across the set. Tolerance questions deliberately cover only brown ±1%, red ±2%, gold ±5% and silver ±10%. Other tolerance colors exist; this is not an exhaustive modern tolerance table. Every code-conversion prompt states the conventional band count and left-to-right order. One uncertainty task leaves direction unknown and asks whether a unique reading is possible.
The sequence introduces band roles and simple decoding before fractional multipliers, reverse encoding and interval work. Later cards mix those skills with error repair and limits of identification. Closely related variants are kept apart; the review scheduler handles long-term spacing. Every card carries the resistor-color-code tag.
You should be comfortable with decimal multiplication and percentages. Interval tasks use exact hypothetical numbers and the inclusive model R × (1 − t) to R × (1 + t), where t is the tolerance percentage divided by 100. They do not teach measurement procedures or include measurement uncertainty. A marked nominal value is not an exact measured value, and tolerance is not a probability distribution or a guarantee under every operating condition.
Text-only prompts make the tested mapping explicit without requiring color discrimination. Visual color identification, automatic reversal of every lookup, leading-zero encodings, special manufacturer schemes, six-band temperature coefficients, component availability and real electrical repair are excluded. Extra permutations were omitted when they added no distinct recall task. This evergreen Electronics deck is not aligned to an examination or curriculum.
Band roles and the tested color facts were checked against Vishay’s resistor color-code chart. SI unit conversions follow the BIPM prefix definitions. Numeric exercises, wording and organization were independently authored. No manufacturer chart artwork, source examples, competitor cards, article exercises or examination questions were copied or adapted.
AI tools assisted with drafting and the original decorative cover. The author manually read every final front and back and checked each applied answer; this does not claim learner testing or measured learning gains. The CC0 dedication covers original wording, examples, organization, metadata and generated cover to the extent applicable rights exist. Facts and cited materials retain their own status. This is independent, unofficial study practice, with no affiliation to or endorsement by Vishay or the other referenced organizations.
Cards in this deck
Card 1
Question
In a conventional 4-band resistor code, what does each band mean from left to right?
Answer
Two significant digits, multiplier, tolerance.
Join the first two digits into one number, then multiply.
Card 2
Question
In a conventional resistor code, what does a black band in a significant-digit position contribute?
Answer
The digit 0.
Keep it in the number. A zero digit does not make the whole resistance zero.
Card 3
Question
Conventional 4-band code, read left to right: orange–white–brown–gold. Nominal resistance and tolerance?
Answer
390 Ω ±5%.
Orange–white gives 39; brown multiplies by 10. The final gold band gives ±5%.
Card 4
Question
In the multiplier position of a conventional resistor code, what factor does black mean?
Answer
×1.
A black multiplier leaves the significant-digit number unchanged.
Card 5
Question
In a conventional 5-band resistor code, what does each band mean from left to right?
Answer
Three significant digits, multiplier, tolerance.
The third band is another digit; the multiplier moves to the fourth position.
Card 6
Question
Conventional 5-band code, read left to right: red–black–blue–black–brown. Nominal resistance and tolerance?
Answer
206 Ω ±1%.
The digits are 2, 0, 6; the black multiplier is ×1. Final brown means ±1%.
Card 7
Question
In the tolerance position of a conventional resistor code, what does gold mean?
Answer
±5%.
This percentage describes a permitted deviation from the nominal resistance in the stated tolerance model.
Card 8
Question
Can gold or silver be a significant digit in a conventional 4- or 5-band resistor code?
Answer
No. Neither color represents a significant digit.
Gold and silver are used for multipliers or tolerances in this scheme.
Card 9
Question
In the multiplier position of a conventional resistor code, what factor does gold mean?
Answer
×0.1.
Divide the significant-digit number by 10.
Card 10
Question
Conventional 5-band code, read left to right: brown–red–white–brown–gold. Nominal resistance and tolerance?
Answer
1.29 kΩ ±5%.
The digits give 129; ×10 gives 1290 Ω. Final gold means ±5%.
Card 11
Question
In the tolerance position of a conventional resistor code, what does red mean?
Answer
±2%.
Read the band by its role: red can mean a digit, a multiplier, or a tolerance.
Card 12
Question
Express 0.24 MΩ in kΩ.
Answer
240 kΩ.
One megaohm is 1000 kiloohms: 0.24 × 1000 = 240.
Card 13
Question
In the multiplier position of a conventional resistor code, what factor does silver mean?
Answer
×0.01.
Divide the significant-digit number by 100.
Card 14
Question
Conventional 4-band code, read left to right: violet–white–gold–silver. Nominal resistance and tolerance?
Answer
7.9 Ω ±10%.
The digits give 79; gold multiplies by 0.1. Final silver means ±10%.
Card 15
Question
A conventional 5-band resistor ends with a gold band. Does having five bands make its tolerance ±1%?
Answer
No. Its final gold band means ±5%.
Band count changes the number of significant digits. It does not replace the tolerance band.
Card 16
Question
Conventional 4-band code for 820 Ω ±2%, written left to right?
Answer
Gray–red–brown–red.
82 × 10 = 820 Ω. The last red band specifies ±2%.
Card 17
Question
In the tolerance position of a conventional resistor code, what does brown mean?
Answer
±1%.
A brown tolerance band means one percent, not one ohm.
Card 18
Question
Conventional 4-band code, read left to right: yellow–blue–silver–gold. Nominal resistance and tolerance?
Answer
0.46 Ω ±5%.
The digits give 46; silver multiplies by 0.01. Final gold means ±5%.
Card 19
Question
Conventional 5-band code for 64.2 kΩ ±1%, written left to right?
Answer
Blue–yellow–red–red–brown.
642 × 100 = 64,200 Ω. Final brown specifies ±1%.
Card 20
Question
For a nominal 1200 Ω resistor with ±5% tolerance, what is the nominal tolerance interval?
Answer
1140–1260 Ω, including both endpoints.
5% of 1200 Ω is 60 Ω; subtract and add 60 Ω.
Card 21
Question
In the multiplier position of a conventional resistor code, what factor does violet mean?
Answer
×10,000,000.
That is ten million, or 10⁷.
Card 22
Question
Conventional 4-band code, read left to right: blue–brown–yellow–brown. Nominal resistance and tolerance?
Answer
610 kΩ ±1%.
61 × 10,000 = 610,000 Ω. Final brown means ±1%.
Card 23
Question
Conventional 4-band code for 9.1 Ω ±10%, written left to right?
Answer
White–brown–gold–silver.
91 × 0.1 = 9.1 Ω. Final silver specifies ±10%.
Card 24
Question
For a nominal 75 Ω resistor with ±2% tolerance, what is the nominal tolerance interval?
Answer
73.5–76.5 Ω, including both endpoints.
2% of 75 Ω is 1.5 Ω.
Card 25
Question
In the multiplier position of a conventional resistor code, what factor does white mean?
Answer
×1,000,000,000.
That is one billion, or 10⁹.
Card 26
Question
Conventional 5-band code, read left to right: green–orange–black–green–red. Nominal resistance and tolerance?
Answer
53 MΩ ±2%.
530 × 100,000 = 53,000,000 Ω. Final red means ±2%.
Card 27
Question
Conventional 5-band code for 3.16 Ω ±1%, written left to right?
Answer
Orange–brown–blue–silver–brown.
316 × 0.01 = 3.16 Ω. Final brown specifies ±1%.
Card 28
Question
For a nominal 0.82 Ω resistor with ±5% tolerance, what is the nominal tolerance interval without rounding?
Answer
0.779–0.861 Ω, including both endpoints.
The deviation is 0.82 × 0.05 = 0.041 Ω.
Card 29
Question
In the multiplier position of a conventional resistor code, what factor does gray (grey) mean?
Answer
×100,000,000.
That is one hundred million, or 10⁸.
Card 30
Question
Conventional 4-band code, read left to right: brown–gray–blue–gold. Nominal resistance and tolerance?
Answer
18 MΩ ±5%.
18 × 1,000,000 = 18,000,000 Ω. Final gold means ±5%.
Card 31
Question
In the nominal interval model, a resistor is 250 Ω ±10%. Is an exact hypothetical value of 275 Ω inside, on a boundary, or outside?
Answer
On the upper boundary, so it is included.
The interval is 225–275 Ω. This exact-number exercise ignores measurement uncertainty.
Card 32
Question
Conventional 4-band code for 36 MΩ ±5%, written left to right?
Answer
Orange–blue–blue–gold.
36 × 1,000,000 = 36 MΩ. Final gold specifies ±5%.
Card 33
Question
For a nominal 2.4 kΩ resistor with ±1% tolerance, what is the nominal tolerance interval in kΩ?
Answer
2.376–2.424 kΩ, including both endpoints.
The deviation is 0.024 kΩ. Keep the same unit throughout.
Card 34
Question
Conventional 4-band code, read left to right: blue–black–orange–gold. A learner gets 0 Ω because black is 0. Correct the nominal value.
Answer
60 kΩ.
Blue–black forms 60, then orange multiplies by 1000. The zero is a digit inside 60.
Card 35
Question
In the nominal interval model, a resistor is 2000 Ω ±2%. Is an exact hypothetical value of 2041 Ω inside or outside?
Answer
Outside.
The inclusive interval is 1960–2040 Ω. The hypothetical value is 1 Ω above the upper limit; measurement uncertainty is outside this exercise.
Card 36
Question
Conventional 5-band code for 91.3 MΩ ±2%, written left to right?
Answer
White–brown–orange–green–red.
913 × 100,000 = 91.3 MΩ. Final red specifies ±2%.
Card 37
Question
Conventional 4-band code, read left to right: green–red–gold–brown. A learner treats gold as the tolerance. Give the correct nominal resistance and tolerance.
Answer
5.2 Ω ±1%.
Gold is the third band, so it multiplies 52 by 0.1. Final brown supplies ±1%.
Card 38
Question
A nominal 6.8 Ω resistor has ±1% tolerance. A learner rounds the deviation to 0.07 Ω before finding the limits. What is the unrounded interval?
Answer
6.732–6.868 Ω.
Use the exact deviation, 6.8 × 0.01 = 0.068 Ω, before subtracting and adding.
Card 39
Question
A conventional 5-band code is listed from one end: brown–green–black–brown–red. Reading direction and physical spacing are unknown. Is one nominal resistance uniquely determined?
Answer
No. Both directions give valid readings.
As listed: 150 × 10 = 1500 Ω ±2%.
Reversed: red–brown–black–green–brown gives 210 × 100,000 = 21 MΩ ±1%. More orientation evidence is needed.
Card 40
Question
A calculation gives 72,000 Ω. A learner writes 72 MΩ. Correct the unit conversion.
Answer
72 kΩ, or 0.072 MΩ.
Divide ohms by 1000 for kiloohms, or by 1,000,000 for megaohms.
Card 41
Question
Does a ±5% resistor tolerance mean there is a 95% probability that its resistance lies in the nominal interval?
Answer
No. Tolerance is not a probability distribution.
It specifies a relative allowed deviation under the applicable specifications. The percentage alone does not give probabilities or cover every operating condition.
Card 42
Question
Does seeing five bands on an unfamiliar real component prove that it uses the conventional 5-band resistor code?
Answer
No. Confirm the component and marking scheme.
These cards assume conventional resistor markings. Special manufacturer schemes and six-band temperature-coefficient markings are outside this deck.
42 cards
Resistor Color Code Flashcards: 4 Bands, 5 Bands & Tolerance
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