Quick Details
Carbon film resistors are a significant improvement on carbon composition. However, in comparison to metal film and metal oxide film, the commercially available range steadily decreases. Metal and oxide film are not more expensive to produce, and have overall better properties.
Description:
Carbon film resistors are a fixed form type resistor. They are constructed out of a ceramic carrier with a thin pure carbon film around it, that functions as resistive material.
Application
Typical use for carbon film resistors is in high voltage and temperature applications. Operating temperatures are up to 15kV with a nominal temperature of 350°C. Examples are high voltage power supplies, radar, x-rays and laser.
Specification
Structure diagram
The construction of resistor (CFR series) shall be as follows:

| Item | Material |
1 | Ceramic core | High alumina ceramic is used. |
2 | Resistor element | The resistor element shall consist of carbon film. |
3 | Terminal | Tinned iron cap. |
4 | Connection | The lead wire, which is plated with solder, shall be mounted to the caps by welding process. |
5 | Lead wire | Soldered or tinned annealed wire. |
6 | Undercoat painting | Electric insulation resin. |
7 | Finishing painting | Epoxy resin is used. |
8 | Indication | Color code. |
1.Electrical Ratings
STYLE | MAX WORKING | MAX OVERLOAD | RESISTANCE VALUE RANGE | CF1/6W / CF1/8W | 200V | 400V | 0.1Ω〜22MΩ | CF1/4W / CF1/4WS | 300V | 600V | 0.1Ω〜22MΩ | CF1/2W / CF1/2WS | 350V | 700V | 0.1Ω〜22MΩ | CF1W / CF1WS | 500V | 1000V | 0.1Ω〜22MΩ | CF2W / CF2WS | 500V | 1000V | 0.1Ω〜22MΩ | CF3W / CF3WS | 600V | 1000V | 0.1Ω〜22MΩ | CF5W / CF5WS | 600V | 1000V | 0.1Ω〜22MΩ | | |
2. Reliable test
ITEM (STANDARD) | PERFORMANCE AND/OR QUALIITY ACCEPTANCE | TEST METHOD | Resistance value Vs Temperature Characteristics | For RX∠100KΩ +350〜-500PPM/℃ 100KΩ≦RX ≦1MΩ 0〜-700PPM/℃ 1 MΩ ∠ RX 0〜-1500PPM/℃ | JIS-C-5202 5.2 Measure resistance (Ro ohm) at room Temperature(To ℃) Measure again the same at 100℃ Higher than room temperature 6 R – RO 10 PPM = * RO (T0+100) –T0 | | |
Short time overload | The resistance variation shall be within±(0.75% + 0.05 ohm) and there Shall be no mechanical breakage | JIS-C-5202 5.5 Apply DC voltage 2.5times the rated Voltage for 5 seconds The leave at room temperature for 30 Minutes then measure MAX overload Voltage 0.50W – 700V (DC) | Insulation resistance | 1000M ohm or more | JIS-C-5202 5.6 In V-BLOCK Lay the resistor on 90° angle metal V Block apply 100VDC between resistor Lead and V block for one Minute And Measure | Voltage endurance | The resistance variation shall be within±(2% + 0.05ohm) and there shall be no mechanical breakage | JIS-C-5202 5.7 Icy the resistor on the 90° angle metal V Block and apply reamed AC voltage for One Minute. Test voltage 0.25W – 500V (AC) 0.50W –700V(AC) | Intermittent overload | Resistance variation shall be Within ±(2.00% + 0.05ohm) | JIS-C-5202 5.8 Apply AC voltage 4 times the rated voltage for 1 second and rest for 25 seconds and Repeat this cycle for 10000±200times leave resistor 30 minutes at room temperature after test and measure Maximum voltage for intermittent Overload.0.50W-700V(AC) | Terminal strength | Resistance variation shall be within ±(0.5% + 0.05ohm) also there Shall be on mechanical breakage | Pull test: apply 2.5kg force to the lead in the direction of lead axislor30±5 seconds. | Heat resistively Against soldering | Resistance variation shall be within ± (1.0%+0.05ohm) also there Shall be on mechanical breakage | JIS-C-5202 7.10 Dip the lead in to a solder bath having a Temperature of 350℃ ± 10℃ up to 4±0.8mm from the body of the resistor at room temperature 3 hours after ,then Measure | Solder ability | More than 95% of the surface of the lead shall be covered by new solder after the leads are dipped in the Solder | JIS-C-5202 6.5 Dip the lead in to a solder bath having a Temperature of 260℃± 5℃ up to 4±0.8mm from the body of the resistor and hold it for 5 ± 0.5seconds then inspect | | |
Humidity load test | Resistance variation be Within ± (3.0% + 0.05ohm) Also there shall be mo mechanical breakage | JIS-C-5202 7.9 In temperature chamber having temperature 40℃± 2℃,relative humidity 90 – 95%, Apply rated voltage 1.5hour and shut voltage 0.5 hour repeat this cycle for 1000 hours, leave in room temperature for lhour after test, then measure | Load life test | The variation of the resistance Shall be within ± (3%+0.05ohm) Also there shall be no mechanical Breakage | JIS-C-5202 7.10 In the constant temperature chamber having Temperature70℃ ± 2℃,apply rated Dc voltage for 1.5hour and shut voltage for 0.5 hour and repeat thin cycle for 1000 hours, leave in room temperature lhour after test, then measure | | |
3.Color refer
Color | 1 st Band | 2 nd Band | 3 rd Band | 4 th Band | Black | 0 | 0 | 0 10 | | Brown | 1 | 1 | 1 10 | | Red | 2 | 2 | 2 10 | ±2.0% | Orange | 3 | 3 | 3 10 | | Yellow | 4 | 4 | 4 10 | | Green | 5 | 5 | 5 10 | | Blue | 6 | 6 | 6 10 | | Violet | 7 | 7 | 7 10 | | Grey | 8 | 8 | 8 10 | | White | 9 | 9 | 9 10 | | Gold | | | -1 10 | ±5.0% | Silver | | | -2 10 | ±10.0% | | |
4. External dimensions
P type

Type | Dimensions |
Normal Size | Small Size | I±2.0 | L±1.0 | ψD | ψd±0.05 | H±2.0 |
CF1/8W | CF1/4WS | 60 | 3.2 | 1.8±0.5 | 0.43 | 28 |
CF1/4W | CF1/2WS | 60 | 6.5 | 2.3±0.5 | 0.45 | 28 |
CF1/2W | CF1WS | 60 | 9.0 | 3.2±0.5 | 0.50 | 28 |
CF1W | CF2WS | 60 | 11.5 | 4.5±1.0 | 0.68
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