BETAPower rating0.25 W at 70 °C ambient
Through-hole carbon film resistor · YAGEO CFR-25
Resistor (1/4 W carbon film) Specifications
Review Resistor (1/4 W carbon film) electrical specifications, operating conditions and package details.
Key specifications
Pick the resistance from the job (current, divider ratio or pull-up), then check the power, I² × R, against 1/4 W derated for the ambient, and the voltage against √(P × R) and 250 V.
Maximum working voltage250 V · and never above √(P × R)
Resistance range1 Ω–10 MΩ E24 values · ±2 % or ±5 %
Operating range−55 to +155 °C
Package details
CFR-25JB-52-1K · Axial (CFR-25)
| Property | Details |
|---|---|
| Manufacturer | YAGEO |
| Part number | CFR-25JB-52-1K |
| Package | Axial (CFR-25) |
| Connections | 2 pins |
| Mounting | Through-hole |
| Lead pitch | 10.16 mm (M-formed 10.0 ± 1 mm) |
| Package code | CFR-25 |
| Thermal reference | About 340 °C/W in free air (from the derating curve) |
Selected part
Manufacturer scope and page conventions
Manufacturer specifications 6 parameters
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| Parameter | Value | Conditions / notes |
|---|---|---|
| Reference | YAGEO CFR series, product specification 2 Sep 2022 | CFR-25 column (1/4 W) |
| Construction | Carbon film on a ceramic core, helically trimmed | Lacquer coated, colour bands |
| Default part | CFR-25JB-52-1K | 1 kΩ, ±5 % (J), bulk |
| Polarity | None | Pins 1 and 2 are interchangeable |
| Footprint | RES40 · 10.16 mm (0.4 in) between pads | Leads formed for a board; YAGEO M-forming is 10.0 ± 1 mm |
| Values | E24 series, 1 Ω to 10 MΩ | ±2 % (G) or ±5 % (J) |
No specifications match. Try a parameter name or a unit.
The colour code is the same for every through-hole resistor; the power rating is not, so check the body size.
Ratings
CFR-25 · 1/4 W
Manufacturer specifications 7 parameters
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| Parameter | Value | Conditions / notes |
|---|---|---|
| Power rating | 0.25 W | At 70 °C ambient |
| Derating | 100 % up to 70 °C, linearly to 0 % at 155 °C | Ambient temperature |
| Maximum working voltage | 250 V | And never above the rated continuous working voltage √(P × R) |
| Maximum overload voltage | 500 V | Short-time overload test limit |
| Dielectric withstanding voltage | 500 V for 60 s | V-block, no breakdown |
| Operating temperature | −55 to +155 °C | Recommended range |
| Peak pulse power | 66 W up to 10 µs, about 0.58 W at 1 s | Single pulse, from the pulse diagram |
No specifications match. Try a parameter name or a unit.
RCWV = √(P × R): a 1 kΩ part reaches its power at 15.8 V; above 250 kΩ the 250 V limit applies first.
Temperature coefficient
Maximum change per °C
Manufacturer specifications 5 parameters
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| Parameter | Value | Conditions / notes |
|---|---|---|
| Below 100 kΩ | −500 to +350 ppm/°C | Carbon film usually falls slightly as it warms |
| 100 kΩ to 1 MΩ | −700 to 0 ppm/°C | Maximum |
| 1 MΩ to 10 MΩ | −1500 to 0 ppm/°C | Maximum |
| Example | 1 kΩ at −300 ppm/°C heated by 50 °C | R = 1000 × (1 − 0.0003 × 50) = 985 Ω |
| Thermal resistance | About 340 °C/W in free air | (155 − 70) °C / 0.25 W |
No specifications match. Try a parameter name or a unit.
Use metal film (±50 ppm/°C or better) where a divider must stay accurate over temperature.
Endurance and overload tests
IEC 60115-1 · allowed resistance change
Manufacturer specifications 8 parameters
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| Test | Condition | Allowed change |
|---|---|---|
| Short-time overload (4.13) | 2.5 × RCWV for 5 s, never above 500 V | ±(0.75 % + 0.05 Ω) |
| Periodic-pulse overload (4.39) | 4 × RCWV (or Umax), 10 000 cycles of 1 s on, 25 s off | ±(1 % + 0.05 Ω) |
| Endurance at 70 °C (4.25) | RCWV for 1000 h (1.5 h on, 0.5 h off) | ±(3 % + 0.05 Ω) |
| Damp heat (4.24) | 40 °C, 90–95 % RH, 56 days at 0.1 × RCWV | ±(3 % + 0.05 Ω) |
| Temperature cycling (4.19) | −55 °C ↔ +155 °C, 5 cycles | ±(1 % + 0.05 Ω) |
| Soldering heat (4.18) | 260 °C for 10 s, 3 mm from the body | ±(1 % + 0.05 Ω) |
| Insulation resistance (4.6) | V-block, 60 s | > 1000 MΩ |
| Robustness of terminations (4.16) | Pull along the leads for 10 s | ≥ 24.5 N (2.5 kg) |
No specifications match. Try a parameter name or a unit.
These are qualification tests of the part, not normal operating conditions.
Colour code
Four-band through-hole resistors
Manufacturer specifications 12 parameters
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| Colour | Digit | Multiplier | Tolerance |
|---|---|---|---|
| Black | 0 | × 1 | — |
| Brown | 1 | × 10 | ±1 % |
| Red | 2 | × 100 | ±2 % |
| Orange | 3 | × 1 k | — |
| Yellow | 4 | × 10 k | — |
| Green | 5 | × 100 k | ±0.5 % |
| Blue | 6 | × 1 M | ±0.25 % |
| Violet | 7 | × 10 M | ±0.1 % |
| Grey | 8 | — | — |
| White | 9 | — | — |
| Gold | — | × 0.1 | ±5 % |
| Silver | — | × 0.01 | ±10 % |
No specifications match. Try a parameter name or a unit.
Read from the end nearest a band: 220 Ω is red–red–brown–gold, 1 kΩ brown–black–red–gold, 10 kΩ brown–black–orange–gold.
Two everyday circuits
LED current limit and a voltage divider
Manufacturer specifications 5 parameters
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| Parameter | Value | Conditions / notes |
|---|---|---|
| LED from 5 V, red (Vf 1.85 V) | 220 Ω → 14.3 mA | (5 − 1.85) / 220 |
| Power in that resistor | 45 mW | 0.0143² × 220; 18 % of 1/4 W |
| Divider from 9 V | 10 kΩ over 4.7 kΩ → 2.88 V | 9 × 4.7 / (10 + 4.7) |
| Divider current and power | 0.61 mA · 3.8 mW in the 10 kΩ | Loading the output lowers it |
| What burns | 100 Ω across 9 V: 810 mW | 3.2 × the rating; the film opens within seconds |
No specifications match. Try a parameter name or a unit.
ProTech’s resistor example runs all of these, including the burnout.
Package
CFR-25JB-52-1K · Axial (CFR-25)
Manufacturer specifications 5 parameters
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| Parameter | Value | Conditions / notes |
|---|---|---|
| Body length | 6.3 ± 0.5 mm | CFR-25 |
| Body diameter | 2.4 ± 0.2 mm | Lacquered, colour bands |
| Leads | Ø 0.55 ± 0.05 mm, 28 ± 2 mm long | Tinned copper |
| Formed for a board | 10.0 ± 1 mm between bent leads | YAGEO M type |
| Footprint | RES40: pads 1 and 2, 10.16 mm apart | 1.778 mm round pads, 0.762 mm drill · Through-hole |
No specifications match. Try a parameter name or a unit.
Leave 1–2 mm between the body and the board for parts that run warm.
Connections by function
Select a pin for its function, connection guidance and electrical notes.