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PTC thermistor

ZMZ31 series of PTC Thermistor are applicable to various types of fluorescent lamp, electronic ballast and electronic energy-saving lamp. The PTC can be connected across the lamp resonator without changing the circuits. It can change hard start of the ballast and electronic energy-saving lamp to preheated start and the preheating time of the filament can come up to 0.4-2 seconds, which will extend the service life of the fluorescent tube by over 3 times.

The application of the PTC thermistor to achieve preheated start is as follows: Immediately after power is switched on, Rt is in normal temperature state and its resistance is far lower than the C2 resistance. The current through C1 and Rt forms a return circuit to preheat the filament. After about 0.4-2 seconds, Rt joule heat temperature exceeds Curie point Tsw and skips into high resistance state of far higher than C2 resistance. The current passes through C1 and C2 to form a return circuit, which causes L resonance and produces high voltage to light the fluorescent tube.

Advanced developments in telephony equipment in recent years have radically altered the protection requirements for both exchange and subscriber equipment. The PTC thermistor must protect the telephone line circuit against over-current, which may be caused the following examples:
* Surges due to lighting strikes on or near to the line plant.
* Short-term induction of alternating voltage from adjacent power lines or railway systems, usually caused when these lines or systems develop faults.
* Direct contact between telephone lines and power lines.

To provide good protection under such conditions a PTC thermistor is connected in series with each line, usually as secondary protection; see Fig.1. However, even with primary line protection (usually a gas discharge tube ),the PTC thermistor must fulfill severe requirements. Surge pulses of up to 2 KV can occur and in order to withstand short-term power induction the PTC thermistor must withstand high voltages. If the line has primary protection, a 220V to 300V PTC thermistor is adequate. Without primary protection,600V PTC device is necessary.. ZEITGEIST manufactures a range of PTC thermistor covering both requirements.

ZMZ6 series as a temperature indicator is small in size and little in calorific capacity. It is so useful for indicating any overheating of power transistors and thyristors in the power sources.

Manufacturer/supplier's information

Company name:		Shenzhen Zeitgeist Electronics Co., Ltd. [ Homepage ]
Business address:		Room 409 Hi-Tech Incubation Centre, 1st Songling Road Futian District, Shenzhen, China
Zip/postal code:		518031
Telephone number:		86-755-82077900
Fax number:		86-755-83655503
Contact name:		Mike Lau [ Email ]

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Product groups: PTC thermistor   thermistor

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