How to Select PTC thermistors for Over Current Protection
Items to be checked
|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|