Successful design of broadband EMC filters necessitates consideration of the actual (broadband) response of all the components used. The correct method can vary widely for different components. The actual terminations of the filter can, under certain circumstances, nullify its effect and hence must definitely be considered. A very convenient method of describing ferrite components is the use of measured dual-gate S parameters. This approach...

Which parasitic parameters are there in the transformer and how can they be measured and subsequently represented in a simulation model? We want to investigate this on the basis of a transformer and investigate using LTspice. “Ideal” transformer models are usually used to make it as easy as possible for the developer and to reduce the computation time in LTspice. Only the inductance values...

Simulation of filter circuits and switching controllers with LTspice With LTspice, Linear Technology has developed a high quality freeware SPICE simulator with no limitations on nodes or components and whose command set is largely compatible with other SPICE versions. Here are a few of the software highlights: Comfortable circuit diagram editor Integrated voltage and current probes Efficiency report for switching controller applications Extensive component...

Ferrite equivalent circuitsMost engineers think of ferrite as an inductive component with which coils, transformers, choke etc. can be manufactured. Losses in the material are accepted as an annoyance and best avoided and are seen to mark a limit of the operating frequency range.The theoreticians had the misfortune of choosing an unsuitable model to describe the frequency dependent parameters, which impedes further understanding like...

As the symbol hints the varistor is a voltage dependent resistor. Primarily it is used for taking care of voltage transients of different shapes. Unlike thermistors it has no practical time delay of its function. R 5.3.1 Function and design Just as thermistors the varistor is fabricated from a compressed and sintered powder compound that consists of silicon carbide (SiC) or zinc oxide (ZnO)....