PTC (positive temperature coefficient ) thermistors help provide protection against power cross, power induction surges and lighting surge defined in ITU, Telcordia, UL. Available in chip, radial-leaded coated and non-coated, SMD, twin vertical surface mount configuration. PTC thermistor overcurrent protector provides reversible, self-resetting protection against over-currents of telecommunication line protector units, improve the reliability of custom premises and network equipment.
Ceramic PTC thermistors can be found providing re-settable line protection at the exchange, monitoring hot spots and protecting ringers, battery feeds, transformers and relay circuits. Also used extensively to protect the mobile phone's battery pack against overcharging in land-based and radio mobile communications.
Advanced developments in telecom equipment in recent years have radically altered the protection requirements of both exchange and subscriber equipment. The PTC thermistor must protect the telephone line circuit against overcurrent, which may be caused by the following examples:
Surges due to lighting strikes on or near to the line plant.
Short-term induction of alternating voltage from adjactent 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; However, even with primary line protection (usually a gas discharge tube), the PTC thermistor must fulfill severe requirements.
Surge pulses of upto 2KV 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. We can manufacture a series of PTC thermistor fulfilling both requirements.
Typical Application of PTC Thermistor in Telecommunication Protection
Central Office Switching Equipment (C. O): Analog and digital line cards, POTS, T1/E1 equipment, xDSL modems and splitters, multiplexers, CSU/DSU, servers.
Primary Protection Modules: MDF (main distribution frame) modules, network interface devices (NIC).
Custom Premises Equipment, also known as subscriber terminal equipment (T. E. ), IT equipment: Modem, phone sets, fax machines, phone wall outlet (plugs), alarm systems, answering machine, PBX systems, ADSL Splitters, internet appliance, POS terminals.
Access Network hardware, LAN WAN equipment, Powered Ethernet systems, VoIP (voice over IP equipment), integrated voice data (IVD), Set-top box (S. B), etc.
Telecom PTC Thermistor Features
Compliant with ITU-T K20 K21 K45
--Basic level lightning surges (10/700μs)
--Basic level power Induction (600V, 1A, 0.2S)
--Power contact criteria A/B (230V, 15min. )
Suitable for continuous connection to main voltage 110/230 VAC in tripped (high ohmic) condition.
Round leadless disk thermistor availble for combined usage of PTC and primary protection, e. G gas arrestor.
Typical Resistance @25C (R25) 10 ohm, 12 ohm, 18 ohm, 20 ohm, 25 ohm, 50 ohm, 55 ohm.
Matching available with narrow resistance tolerance.
Tight resistance tolerance maintained after switching.
Negligible resistance drift after soldering or switching.
AMWEI Thermistor Co., Ltd., professional manufacturer of PTC & NTC thermistors (THERMally sensitive resistors) and thermistor temperature sensors probe. PTC (Positive Temperature Coefficient) thermistor for over-current & overload protection, telecom, lighting switching, temperature sensing & protection, self-regulation heating, motor starting. NTC (Negative Temperature Coefficient) thermistor application covers power thermistor for inrush current suppressing limiting, NTC thermistor for temperature measurement, indicator, temperature compensation, temperature control, in either radial leaded, axial leaded or surface mount configuration. Can also make custom thermistors assemblies and temperature probes, housed in either stainless steel, copper, plastic, teflon, aluminum, epoxy and heat shrinkable tubing, such as air/gas temperature sensors, surface temperature sensors and immersion temperature sensors, etc.
The 2 founders of AMWEI came from Nonmetal Material Research Institute of Huazhong University of Science and Technology, once as a visiting scholar in Japan in late 1980, and took charge of Chinese first imported PTC production line. Thorough successive hard work of a group of specialists in ceramic sensitive material, welding technology, packaging technology, we own core know-how in powder formula and key production technics. Our NTC thermistor features with high accuracy, fast response and long time stability. PTC thermistor switch life and voltage withstanding capacity is leading in China.
AMWEI PTC R&D now aims at low resistivity and miniaturization.
We maintain the highest quality standards through continuous employee training, rigorous internal auditing. We take continuous improvement as a primary business objective. SPC, MSA, 6-Sigma techniques are being applied throughout the manufacturing process in an endless loop of quality improvement. ISO9001: 2000 certified in 2003.
AMWEI PTC and NTC thermistor has been widely applied in the field of telecom & network, HVAC & R, home electric appliance, white goods, food service, consumer electronics, lighting, office automation equipment, medical, automotive, consumer electronics, meter & instrumentation, data logger, power supply and transformer, industrial process control etc.
HVAC applications include indoor/outdoor air temperature, duct air temperature & water temperature. Thermistor sensors play a vital part in the efficiency of white goods by measuring and controlling the temperature of water, steam, air, food, as well as the electronic circuitry. Thermistors can be found all around the home in washing machines, dishwashers, cookers, microwave ovens, irons, toasters, refrigerators and deep freezers. Electronic sensors offer improved accuracy over electro-mechanical solutions and can be designed to perform over a wide range of temperatures and specifications.
Food service applications include food safety, and commercial cooking equipment. Automotive applications include climate control, fuel level/temperature, coolant & engine temperature, and combustion controls. AMWEI has a professional engineer team for customer product design and application assistance. Customer satisfaction is our honor and effort target, fast response is our pledge.
Annual production capacity: 90 million pieces, Production area: 3700 square meters.
Applying AMWEI thermistor products, you can get high quality product, fast delivery. Contact us to get the thermistor sensor appropriate to your product.
