PPTC‘s methods of selction and steps

Step 1: Determine the circuit parameters

You need to determine the following parameters of the circuit:

Maximum working ambient temperature

Standard operating current

Maximum operating voltage

Maximum interrupt current

Step 2: selct the circuit maximum ambient temperature and standard work the current JDTFUSE devices can accommodate

Reduction ratio [holding current (A)] table and selct the temperature that most closely matches the circuit maximum ambient temperature of the ambient temperature (℃). Browse bar to access equal to or greater than the value of the standard operating current of the circuit. Now see the row of the left-most access to the most suitable for the circuit device family.

 

Step 3: The selcted device's maximum electrical rating and circuit maximum working voltage and current interrupted compare

Electrical Characteristics table to verify whether the selcted parts will be used in Step 2 to the maximum operating voltage of the circuit and interrupt current. Consult the device operating voltage (Vmax) and maximum interrupt current (Imax). Make sure that the Vmax and Imax is greater than or equal to the maximum working voltage of the circuit and the maximum interruption current.

 

Step 4: Determine the action time

The operation time is the amount of time when the fault current through the device when this device is switched to the high resistance state. In order to provide the expected protection function, a clear JDTFUSE device operation time is very important. If you selct the device action too quickly, there may appear abnormal operation or malfunction. If the device action is too slow, before the device action and limit the current protection devices may be damaged.

Time curve at 25 ℃ typical action operation time characteristics of the expected fault current decided that JDTFUSE devices can accept, if you can not, go back to Step 2 to selct another alternative devices.

 

Step 5: Verification Environment Operating Temperature

Ensure that the application of the minimum and maximum ambient temperature in the JDTFUSE device operating temperature range. The most JDTFUSE devices operating temperature range between -40 ℃ to 85 ℃, will reach 125 ° C in some special cases.

 

Step 6: Dimensions verify WHPTC devices

Dimensions table to compare Dimensions and applications of the of your choice WHPTC device space conditions.