Positive Temperature Coefficient (PTC) Thermistors are used in a wide variety of applications to protect sensitive components against Over-Current conditions (over-current protectors). The PTC is unique in its ability to limit excess current during fault conditions, and then automatically reset to a normal operating mode when the fault is removed. Select a part from our Standard Over-Current Protectors or contact TU engineering to design a PTC to meet your specific application requirements.
PTC Thermistors are semiconducting ceramic devices that exhibit the ability to switch from a low resistance state to a high resistance state depending on their body temperature. The PTC element is normally placed in series with the component that requires over-current protection.
FEATURES:
- Fast Switching
- No Electrical Noise
- Virtually Unlimited Life
- Self-Resetting
- No Contacts
- Automatic Operation
- Efficient
TYPICAL APPLICATIONS:
- Telephone Line Fault Protection
- Transformer Protection
- FHP Motor Protection
- Transistor Protection
To see our Data Sheets for Over-Current Protectors click here.
NOTES:
- Maximum Voltage is listed as DC or 60 Hz. AC.
- Maximum No Switch Current (Ins) is the maximum current that the PTC can pass without switching into its high resistance state.
- Minimum Must Switch Current (lms) is the minimum current that is necessary to switch the PTC into its high resistance
- Ins is calculated at the maximum ambient temperature, while lms is determined at the minimum ambient temperature. For ATP standard products, Tamin is 0 °C and Tamax is 50 °C.
NOTES:
The PTC's listed on the standard Over-Current Protector table are often modified to fit each individual application. By varying the Resistance at 25 °C, Switch Temperature, or size of the part, we can customize a PTC to meet your requirements.
In general, PTCs cannot be connected in series to obtain higher voltage ratings. One device would heat more rapidly than the others and prevent the other PTCs from switching. However, PTC thermistors can be used in parallel to increase their current rating.