Monday, August 26, 2013
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Wednesday, August 14, 2013
Happy independence day to all Pakistanis. As a independence day gift, we are releasing high tech interest base research on electromagnetic pulse as a part of this blog.
The term electromagnetic pulse (sometimes abbreviated EMP) is a burst of electromagnetic radiation that results from an explosion (usually from the detonation of a nuclear weapon) and/or a suddenly fluctuating magnetic field. The resulting rapidly changing electric fields or magnetic fields may couple with electrical/electronic systems to produce damaging current and voltage surges.
In military terminology, a nuclear bomb detonated hundreds of kilometers above the Earth’s surface is known as a high-altitude electromagnetic pulse (HEMP) device. Nuclear electromagnetic pulse has three distinct time components that result from different physical phenomena. Effects of a HEMP device depend on a very large number of factors, including the altitude of the detonation, energy yield, gamma ray output, interactions with the Earth’s magnetic field, and electromagnetic shielding of targets.
The case of a nuclear electromagnetic pulse differs from other kinds of electromagnetic pulse (EMP) in being a complex electromagnetic multi-pulse. The complex multi-pulse is usually described in terms of three components, and these three components have been defined as such by the international standards commission called the International Electrotechnical Commission (IEC).
The three components of nuclear EMP, as defined by the IEC, are called E1, E2 and E3.
Capacitor Comparison for EMP use:
- Ceramic capacitors range from low to high voltage but are vulnerable to aging (and change in crystal structure over time) and have to be reheated up to curie point to reverse the aging effect.
- Polymeric capacitors produce up to 60,000V but temperature stability is poor; inappropriate for radio frequency applications due to excessive dielectric heating.
- Glass Capacitors although have a high working temperature and are very stable but their capacitance is in picofarads.
- Ultra-capacitors have a maximum working voltage upto 24.4 V and hence need a large amount to series connections to build up an EMP device.
Class II ceramic capacitors provide bet material for the EMP effect to successfully occur over a voltage of ~ 50,000V.
To further improve the dissipation rate electrical grade castor oil or similar high dielectric constant fluid can be used along with extended foil plates in combination with the ceramic capacitors to use their high voltage to generate EMP.