points must be paid attention to when using over-九游会下载

in order to avoid short circuit,burning accident or failure when using the thermal resistors, 

the following special attention should be paid to when using and testing ptc thermistors:

1. don't  use test ptc thermistors beyond "maximum working current" or "maximum working voltage".

2. don't  use test ptc thermistors in water, oil, or flammable explosive gases;

other points must be pay attention to ptc thermistors when using and storage:

1.clean:

freon, trichloroethane, or tetrachloroethylene mild detergent are suitable for cleaning thermistors, 

also can use the method of ultrasonic cleaning, but some detergent may damage the performance of the thermal resistor.

2.welding

it should be noted that in order to prevent damage due to excessive heating in welding,

 the ptc thermistors must comply with the following requirements::

dip soldering                                                                                               iron welding

temperature of welding pool　　　                                                             max. 260 ℃　　　　  max. 360℃

brazing time　　　　　　　　　　                                                                max. 10s 　　　　　  max. 5 s

the minimum distance from the welding point to the ptc thermistor　 　   min. 6mm 　　　　　min. 6mm

the resistance value will be changed in a bad soldering condition.

3.coating and potting

when coating and potting the ptc thermistor, mechanical stress is not allowed due to the different thermal expansion in 

the processing of solidifying and after processing.

when coating and perfusion are applied to the ptc thermistors, mechanical stress is not allowed due to the different thermal expansion in 

the processing of solidifying and after processing. be careful to use perfusion materials or fillers.

it is not allowed to exceed the upper limit temperature of the ptc thermal resistor during curing.

please use caution with potting material.

it is not allowed to over the ceiling temperature of ptc thermistor during solidifying.in addition,

be aware that, potting material must be chemically neutral.the reduction of titanate ceramics in ptc thermistors 

may lead to reduced resistance and loss of electrical properties,,which may cause partial overheating on the ptc thermistor and cause its damaged.

4.storage conditions and time limit

if stored properly, the storage period of ptc thermistor has no time limits.

in order to keep the solderability of ptc thermistor,they should be storaged in the circumstances without corrosive atmosphere , 

at the same time pay attention to the air humidity, temperature and container material.

thermal resistors components should be storaged in the original packaging as far as possible. .

touch on the metal cladding of not welding ptc thermistor may cause the degradation of weldable performance.

some specifications and product performance of thermal resistor or may be changed if exposure to moisture or under high temperature,

such as solderability of tin lead etc..

but thermistors can be long-term preservation if saved under the normal storage condition of electrical components.