PTC Thermistor Nickel Iron Alloy Wire PTC-7 for Resistance Wire
PTC thermistor alloy wire finds application in various fields due to its unique characteristics. Here are some common applications of PTC thermistors:
Overcurrent protection: PTC thermistors are widely used in electrical circuits for overcurrent protection. When a high current flows through the PTC thermistor, its temperature increases, causing the resistance to rise rapidly. This increase in resistance limits the current flow, protecting the circuit from damage due to excessive current.
Temperature sensing and control: PTC thermistors are used as temperature sensors in applications such as thermostats, HVAC systems, and temperature monitoring devices. The resistance of the PTC thermistor changes with temperature, allowing it to accurately sense and measure temperature variations.
Self-regulating heaters: PTC thermistors are employed in self-regulating heating elements. When used in heaters, the PTC thermistor’s resistance increases with temperature. As the temperature rises, the resistance of the PTC thermistor also increases, leading to a decrease in power output and preventing overheating.
Motor starting and protection: PTC thermistors are utilized in motor starting circuits to limit the high inrush current during motor startup. The PTC thermistor acts as a current limiter, gradually increasing its resistance as the current flows, thereby protecting the motor from excessive current and preventing damage.
Battery pack protection: PTC thermistors are employed in battery packs to protect against overcharging and overcurrent conditions. They act as a safeguard by limiting the current flow and preventing excessive heat generation, which can damage the battery cells.
Inrush current limitation: PTC thermistors serve as inrush current limiters in power supplies and electronic devices. They help reduce the initial surge of current that occurs when a power supply is turned on, protecting the components and improving system reliability.
These are just a few examples of the applications where PTC thermistor alloy wire is used. The specific application and design considerations will determine the exact alloy composition, form factor, and operating parameters of the PTC thermistor.
Chemical composition:
| Name | Code | Main Composition | |||||
| Fe | S | Ni | C | P | Standard | ||
| Temperature Sensitive Resistance alloy wire | PTC | Bal. | ≤0.01 | 77~82 | ≤ 0.05 | ≤0.01 | Q/320421PTC4500-2008 |
Specifications and tolerances
| Diameter | 0.05 | 0.10 | 0.15 | 0.16 | 0.17 | 0.18 | 0.19 | 0.20 | 0.21 | 0.22 | 0.23 | 0.24 | 0.25 |
| Tolerance | ± 0.003 | ± 0.005 | ± 0.008 | ||||||||||
Temp.Coeff.Of resistance(20ºC)
| Type | P-4500 | P-4000 | P-3800 | P-3500 | P-3000 | P-2500 |
| 0~150ºCaverage × 10%%Z | 4500 | ≥4000 | ≥3800 | ≥3500 | ≥3000 | ≥2500 |
Resistivity (20ºC)(μΩ.m)
| Type | P-4500 | P-4000 | P-3800 | P-3500 | P-3000 | P-2500 |
| at20ºCresistance ±5%μΩ.m | 0.19 | 0.25 | 0.27 | 0.36 | 0.40 | 0.43 |
The table for resistance
| Product | ±0.5%Ω/m | Dia.(mm)and cross-sectional area (mm²) | ||||||||||||
| 0.05 | 0.10 | 0.15 | 0.16 | 0.17 | 0.18 | 0.19 | 0.20 | 0.21 | 0.22 | 0.23 | 0.24 | 0.25 | ||
| 0.00196 | 0.00785 | 0.00176 | 0.0201 | 0.0227 | 0.0255 | 0.0284 | 0.0314 | 0.0346 | 0.0380 | 0.0415 | 0.0452 | 0.0491 | ||
| P-4500 | 96.93 | 24.20 | 10.79 | 9.45 | 8.37 | 7.45 | 6.69 | 6.05 | 5.49 | 5.00 | 4.58 | 4.20 | 3.87 | |
| P-4000 | 127.55 | 31.84 | 14.20 | 12.43 | 11.014 | 9.80 | 8.80 | 7.69 | 7.22 | 6.58 | 6.02 | 5.53 | 5.09 | |
| P-3800 | 137.75 | 34.39 | 15.34 | 13.43 | 11.89 | 10.59 | 9.51 | 8.60 | 7.80 | 7.11 | 6.51 | 5.97 | 5.50 | |
| P-3500 | 183.67 | 45.85 | 20.45 | 17.91 | 15.86 | 14.12 | 12.68 | 11.46 | 10.40 | 9.47 | 8.67 | 7.96 | 7.33 | |
| P-3000 | 204.08 | 50.95 | 22.72 | 19.90 | 17.62 | 15.68 | 14.08 | 12.73 | 11.56 | 10.52 | 9.63 | 8.84 | 8.14 | |
| P-2500 | 219.38 | 54.77 | 24.43 | 21.39 | 18.94 | 16.86 | 15.14 | 13.69 | 12.42 | 11.31 | 10.36 | 9.51 | 8.75 | |
The weight per spool
| specification (mm) | ≤0.05 | >0.05~0.10 | >0.10~0.15 | >0.15~0.25 | |
| Weight per spool | Standard weight | 20 | 30 | 100 | 300 |
| Lesser weight | 10 | 20 | 50 | 100 | |
Elongation(%)
| Standard | ≤0.05 | >0.05~0.10 | >0.10~0.15 | >0.15~0.25 |
| Alloy wire (soft)elongation | 10% | 12% | 16% | 20% |
