Spark gaps as protective devices
Smaller spark gaps are often used to protect sensitive electrical or electronic equipment from high voltage surges. In sophisticated versions of these devices (called gas tube arresters), a small spark gap breaks down during an abnormal voltage surge, safely shunting the surge to ground and thereby protecting the equipment. These devices are commonly used for telephone lines as they enter a building; the spark gaps help protect the building and internal telephone circuits from the effects of lightning strikes. Less sophisticated (and much less expensive) spark gaps are made using modified ceramic capacitors; in these devices, the spark gap is simply an air gap sawn between the two lead wires that connect the capacitor to the circuit. A voltage surge causes a spark which jumps from lead wire to lead wire across the gap left by the sawing process. These low-cost devices are often used to prevent damaging arcs between the elements of the electron gun(s) within a cathode ray tube (CRT).
Suntan ( www.suntan.com.hk ) has supply Spark Capacitors .The Spark Capacitors - TS21 features are: Spark gap capacitors are designed to provide a reliable discharge path for stray, transient over voltages and static voltage build-up. The construction of the spark gap enable the circuit designer to reduce cost by specifying lower voltage components with the assurance that over-voltage conditions will be prevented.
