How to Select PTC thermistors for Over Current Protection
Items to be checked | Selection criteria | |
How much (in volts) is the power supply voltage of the circuit in which PTC thermistor is used? (Preventing PTC thermistor from being damaged) | -> | Power supply voltage ≤ Maximum voltage of PTC thermistor |
When the circuit is operating normally, how much (in amperes) is the current that flow through PTC thermistor? (Preventing PTC thermistor from malfunctioning) | -> | Normal current ≤ Non-operating current of PTC thermistor |
When something abnormal such as a short circuit has occurred, how much (in amperes) is the current that flows through PTC thermistor? (Ensuring reliable protection) | -> | Abnormal current ≧ Operating current of PTC thermistor |
PTC thermistor application environment condition, esp. ambient temperature | -> | PTC thermistor reference temperature (also called Switch temperature or Curie temperature) >maximum operating ambient temperature |