Impedance Stabilizing Network

For measuring EMI, we need to use an ISN ( Impedance Stabilization Network ). In off-line power supplies, this becomes a LISN (Line Impedance Stabilization Network) — also called an AMN (Artificial Mains Network). See Figure 9-2 for a simplified schematic. Note that the LISN, as recommended for CISPR-22 compliance, is detailed in CISPR 16. 

As the quinone stabilizer is consumed, the peroxy radicals initiate the addition chain propagation reactions through the formation of styryl radicals. In dilute solutions, the reaction between styrene and fumarate ester foUows an alternating sequence. However, in concentrated resin solutions, the alternating addition reaction is impeded at the onset of the physical gel. The Hquid resin forms an intractable gel when only 2% of the fumarate unsaturation is cross-linked with styrene. The gel is initiated through small micelles (12) that form the nuclei for the expansion of the cross-linked network. 

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