一.概述 HLMZ2系列PTC熱敏電阻是一種自動(dòng)保護(hù)、自動(dòng)恢復(fù)使用、無觸點(diǎn)、無噪音、無火花的“萬次保險(xiǎn)絲”，或稱“自恢復(fù)保險(xiǎn)絲”，是繼“溫度保險(xiǎn)絲”和“溫度開關(guān)”之后推出的第三代保護(hù)器件。適用于萬用表、充電器、小型變壓器、智能電度表、數(shù)字萬用表、微電機(jī)、小型電子儀器等線路中做過流、過熱保護(hù)。二、應(yīng)用實(shí)例及外形圖 應(yīng)用原理如下圖所示：把PTCR串聯(lián)在負(fù)載電路中，當(dāng)電路處于正常工作狀態(tài)時(shí)，通過PTCR的電流不超過額定電流即不超過PTCR的最大不動(dòng)作電流，PTCR處于常態(tài)，阻值較小，不會(huì)影響被保護(hù)電路的正常工作。當(dāng)電路出現(xiàn)故障，電流大大超過額定電流，PTCR驟然發(fā)熱，呈高阻態(tài)，使電路處于相對(duì)“斷開”狀態(tài)，達(dá)到保護(hù)目的。當(dāng)故障排除后，PTCR自動(dòng)恢復(fù)正常工作。三、產(chǎn)品編號(hào)備注：
1. 除上表所列規(guī)格型號(hào)之外，可按用戶要求設(shè)計(jì)生產(chǎn)其它規(guī)格要求的PTC熱敏電阻器。
2.HLMZ2系列PTC熱敏電阻已取得關(guān)于ROHS限制的六種有毒、有害物質(zhì)含量的SGS測(cè)試報(bào)告。五、應(yīng)用實(shí)例實(shí)例I
HLMZ2-6 20Ω型PTC熱敏電阻是我司從程控交換機(jī)用程控保安單元中演變出來的一種應(yīng)用于485通信接口的保護(hù)元器件。該產(chǎn)品串接在485通信接口中，可有效防止通信線路因意外破損或人為損害而導(dǎo)入的220V市電對(duì)該接口的損壞，也可適當(dāng)降低雷電感應(yīng)通信線路對(duì)該接口的影響。該產(chǎn)品具有穩(wěn)態(tài)阻值小、額定電流低、耐壓能力高、響應(yīng)速度快等特點(diǎn)，是485通信接口實(shí)現(xiàn)保護(hù)的經(jīng)濟(jì)適用的選擇。應(yīng)用電路PTC Thermistors for Restricting Overloading and Current Main CategoriesAccording to the appearance, the PTC Thermistors for restricting overloading and current can be divided into some categories, such as porcelains, shellies, wrapping and pasters. Working TheoriesThe restricting overloading protection PTC Thermistor is connected in series in the overloading circuit. when the circuit is in the normal working state , the current flowing through the PTC Thermistor is not high enough to make the temperature exceed the Curie temperature for protection ,and it is always in the low state of resistance. When the circuit breaks down and the return circuit current increases, the resistance of restricting overloading protection PTC Thermistor goes up sharply for being warm, until the circuit is cut off. After the clearing of the circuit trouble, the PTC Thermistor begins to cool and come back to the state of low resistance, and then the circuit enters normal working condition. When the circuit breaks down next time, the PTC Thermistor can enter the state of protection again. ApplicationsRestricting overloading protection PTC Thermistor is mainly used in the remote alternating machinery, remote control telephones, distributing frames, safe-guard units, voltage transformers, crystal conductors, automats, cars, washing-machines, fluorescence lamps, computer peripheral equipments, motor starters, household appliances, electronic instruments and micro power equipments at present. AdvantagesCompared with the traditional fusing filament, the restricting overloading protection PTC Thermistor reacts fast, contactless, flameless, noiseless and recoverable. Meanwhile, compared with the organic high molecule PTC Thermistor, the pottery restricting current PTC Thermistor of normal temperature changes little after numerous protection with a better performance of withstanding voltage. Additionally, it can resume steadily and has a good performance. If hotly-coupling installed with overloading, it can repair the circuit trouble caused by the double effects of overheating and overcurrent