This slide reviews some terminology starting with working or operator voltage, typically given in units of Vrms, the voltage that may be applied continuously across the isolation barrier. Typical ranges can be from 300 Vrms to 1500 Vrms. The isolation or transient voltage, also given in Vrms is the voltage that may occur temporarily across the barrier, tested for one minute during qualification, an example range is 2.5 kVrms to 6 kVrms. Basic or functional isolation is an isolation level which assumes a single level of isolation at a particular strength. That could be 2.5 kVrms or 1 kVrms, depending on the specification that the engineer is designing to. This is applicable in most industrial applications, equipment that is less than 400 Vrms, and for consumer electronics which is mostly rated at a 560 Vpk continuous or 4 kVpk transient voltage. Reinforced isolation is another isolation level; it assumes a single level of isolation providing the same reliability as a two-layer isolation, essentially a layer of two separate isolation systems, one of which could be a back-up. It is typically applicable for medical applications and AC equipment greater than 400 Vrms. For a component-level reinforced rating, VDE requires certification testing at a 10 kVpk surge voltage level. Common mode transient immunity or CMTI is the rapid change in reference potential from primary to secondary, given in the units of dV/dt up to which no false toggling of the output will occur. A typical example of a CMTI rating would be ±35 kV/µs. Lastly, partial discharge is a phenomena exhibited by insulator material when subjected to high electrical stresses and is caused by the localized dielectric breakdown of voids or imperfections present which do not immediately bridge the space between the two conductors. Typically, it is measured in pico-Coulombs, using the apparent charge method. 100% of units are production tested for partial discharge. When discussing PD, silicon dioxide is a very resilient insulation material.