In summary, CSTs are used for controlling and protecting circuits as well as detecting loads in power supplies. EPCOS has two new CST series suited for compact DC/DC converters which feature integrated primary winding, space-saving design, and transfer ratios from 1:20 to 1:125. The first series is compatible with existing designed based on an EE5 core and the second series was developed with a much smaller E4.2 core.