Spike protection

The protection levels are categorised into knife resistance (KR) and spike protection (SP), with three protection levels for each (levels 1,2, and 3). The maximum penetration is measured with two energy levels, El and E2, with permissible penetrations of 7 mm and 20 mm, respectively. 

For spike protection, the material should also pass the knife resistance test and should not allow any penetration of the spike at energy level El. The spike protection level is investigated in addition to the knife resistance level. 

PSDB=Police Scientific Development Branch KR=knife resistance SP=spike protection. 

A good example of a prescriptive approach to quality assessment is the protocol outlined in Figure 15.2, published by the Environmental Protection Agency (EPA) for laboratories involved in monitoring studies of water and wastewater. Independent samples A and B are collected simultaneously at the sample site. Sample A is split into two equal-volume samples, and labeled Ai and A2. Sample B is also split into two equal-volume samples, one of which, Bsf, is spiked with a known amount of analyte. A field blank. Dp, also is spiked with the same amount of analyte. All five samples (Ai, A2, B, Bsf, and Dp) are preserved if necessary and transported to the laboratory for analysis. 

The inductance in the d.c. link may cause a reverse voltage spike across the power diodes or thyristors as a residt of the decay of the reverse current (release of its stored energy). A power deviee may be protected against such voltage spikes through tin R-C snubber circuit, as shown in Figure 6.37. (This circuit is discussed later.)... 

Surge protection on HV side is adequate to absorb direct surges. The transferred surges from HV side to the LT side are too feeble to cause any harm. In case of static switchings, on LT side, however, spike arrester will be essential. Section 6.14.1. 

Ultramodern techniques are being applied to the study of corrosion thus a very recent initiative at Sandia Laboratories in America studied the corrosion of copper in air spiked with hydrogen sulphide by a form of combinatorial test, in which a protective coat of copper oxide was varied in thickness, and in parallel, the density of defects in the copper provoked by irradiation was also varied. Defects proved to be more influential than the thickness of the protective layer. This conclusion is valuable in preventing corrosion of copper conductors in advanced microcircuits. This set of experiments is typical of modern materials science, in that quite diverse themes... combinatorial methods, corrosion kinetics and irradiation damage... are simultaneously exploited. 

Platinised Ti, Ta or Nb < 1000 Am/m (consumption) Discontinuities in Pt coat protected by oxide film on subtrate sensitive (< lOOHz) a.c. ripple in d.c. or negative current spikes causing electrode consumption maximum operating potential with Ti substrate 9 V... 

Shriver-Lake L.C, Shubin Y., Ligler F.S., Detection of staphylococcal enterotoxin B in spiked food samples, J. Food Protect. 2003 66 1851-1856. 

The resistor (R1) is used to control the capacitor. The first diode (D1) can be either a single diode (halfwave rectified) or a bridge rectifier. The second diode (D2) is to protect the capacitor from the HV spike from the coil and should be large enough to provide blocking resistance to this spike. The third diode (D3) similarly prevents the capacitance discharge from flowing back to the coil. 

---