Overvoltage suppression device (device)
The gas discharge tube (GDTs) is usually used for the protection of telecommunication lines, data communication lines and other equipment (equipment) of the signal line, is not affected by the surge voltage. The device can withstand up to 40000 amps of inrush current, and thus is an ideal choice to reduce lightning transients.
A varistor (variable resistor) allows the current generated by the high transient voltage to avoid sensitive devices. Divided into two main types:
Multilayer varistors (MLVs) can provide protection for 0-120V DC powered sensitive devices with low energy transients (0.05-2.5 joules). These multilayer varistors are most commonly used for ESD protection.
Metal oxide varistor (MOVs) can provide 0.1-10000 Joule rated energy, so that sensitive components to avoid transient current. For the low voltage DC power supply port or signal port, the varistor combines the advantages of high surge and small size disc, which provides an ideal choice for space saving design. For example, a 10mm varistor can withstand up to 2000A of inrush current, which is the same size as the standard MOV withstand maximum surge current of four times. The device can protect the circuit from damage caused by electrical threats, such as lightning induced interference, system switching transients, and abnormal fast transients of the power supply
Polymer ESD suppressor with low junction capacitance (~ 0.05pF) and fast clamping ability, so it is an ideal choice for high-speed digital I/O and RF lines. Low junction capacitance helps ensure no error or distortion.
Transient voltage suppressor (TVS) diodes protect a variety of circuits and components from the threat of a variety of common DC power lines. The diode p-n junction cross section is much larger than the conventional diode, which can damage without the larger current conduction to, the transient voltage is suppressed to lower than that of the other technical level. Transient power rating between 400 W -15000 W, maximum 15000A@ 8x20us waveform. Semiconductor diode protection array (SPA) is designed to protect analog and digital signals from ESD and other transient overvoltages. In addition, it is possible to provide ESD protection in a smaller space using a multi-channel array, and the clamp voltage is lower than other techniques, thus providing the best possible protection.
The semiconductor arrester design using suppression telecommunications and data communication equipment transient over voltage, current and can reach the breakdown voltage of a few nanoseconds as high as 5000A to guide.
Over current protection device
Fuse is the most commonly used over current protection device, divided into fast and slow off (delay) type. The second type can be repeated in a short time but the current occurs in the current pulse, the number of repeated replacement to a minimum. In portable applications, small surface mount fuses are often used to save space and block over voltage and short circuit current.
PTC thermistor is a reusable device instead of a fuse. When the current increases, increase the PTC resistance and automatically limit the current. Under normal circumstances, the use of polymer (PPTC) materials, can be formed between the impedance and temperature of the obvious inflection point. Once the overload disappears, the PPTC cools and restores the circuit to normal operation. Therefore, no need to replace the fuse.