PTC Thermistors POSISTOR® Application Manual 2008 by Murata Manufacturing Co.,Ltd.

More catalogs by Murata Manufacturing Co.,Ltd. | PTC Thermistors POSISTOR® Application Manual 2008 | 15 pages | 2013-07-26

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Page 13 of PTC Thermistors POSISTOR® Application Manual 2008

!note · this pdf catalog is downloaded from the website of murata manufacturing co ltd therefore it s specifications are subject to change or our products in it may be discontinued without advance notice please check with our sales representatives or product engineers before ordering · this pdf catalog has only typical specifications because there is no space for detailed specifications therefore please approve our product specifications or transact the approval sheet for product specifications before ordering r16e.pdf 08.9.25 practical applications of posistor® 4 3 for current control 1 over current protection if a circuit s current limit is exceed a posistor can react to the higher current self heating and quickly protect the circuit fig 15 100k 10k rl transistor 1 -b posistor 0.1µf 100k 10k posistor rl -b motor 2 posistor motor power source 2.2 10µf m posistor 75 power source 160v power source 30µf power circuit 3 posistor 27 160v 30µf coaxial cable t.v antenna booster posistor ptgl04 ptgl07 ptgl12 fig 15 protection from over current 2 delay circuit a delay function can be created by using the dynamic characteristics of posistor there are two methods one is with the posistor connected in parallel with a relay as in fig 161 and the other is similar but with series connection as in fig 162 and 3 4 posistor 1 r time adjustment power source relay 2 posistor for delaying 3 relay posistor for heater fig 16 delay operation of relay ptgl 3 for the control of inrush current a switching power supply has large inrush current when it first turns on if posistor is used instead of a resistor or an ntc thermistor the posistor works as inrush current limiter the posistor self heats due to over current in the case of relay or thyristor s failure and will trip to high resistance quickly shutting off the current fig 17 thyristor posistor fig 17 inrush current limit circuit 4 for motor starter if the posistor is used as a contactless starter rely for compressors as in refrigerators freezers and air conditioners strong starting torque can be generated fig 181 to 4 1 rsi motor 2 csir motor 3 crs motor 4 psc motor fig 18 motor starting pth6m pth7m pthtm relay 11