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A super quiet EP13 size flyback transformer. Primary inductance is 4.31mH +/- 10%. Switching frequency is 60 KHz minimum. The input is rated at 120V. There are 2 outputs rated at 2.5V/600mA and an aux rated at 17V/20mA. The power rating is 3.4VA, but it could handle twice that at 6.8VA. The design reduces electrical…

The forward converter does appear similar to the flyback transformer, but it is actually very different. The forward converter transfers its energy instantly (transformer action) unlike the flyback which stores and then releases that stored energy to the SEC side… See below for a general schematic of this forward converter… As one can see there…

Most everything we use of convenience and need these days is electrically powered. Most often we have access to a source of voltage at one, or maybe two particular values. Unfortunately in many cases the very items we use and need internally have components that do not run at the voltages available to us. Many…

In transformer design, there is an equation most of us are familiar with. This equation is known as the “transformer design equation”. This equation is applicable for inputs that are of most any voltage. The usual voltage forms are sinusoids as seen in lower frequency silicon steel type transformers such as UL Class 2 recognized…

One flavor of a high frequency switching transformer is known as a push-pull transformer. A push–pull transformer is a DC-to-DC switching transformer; it is often used to change a power supply’s DC voltage. These power supplies are known as switched-mode-power-supplies (SMPS). Older, linear power supplies often used low frequency, heavy silicon steel type transformers to…

In the spirit of the season, CET Technology would like to wish everyone Happy Holidays and a Happy New Year with our Custom Magnetics Song! Enjoy! Twelve Days of CET Christmas On the first day of Christmas, CET sent to me A Toroidal Transformer for my radio and TV. On the second day of Christmas,…

Predicting the final temperature of a part is not always an easy thing to do. It becomes a complex task for complex parts. We’re going to predict this final temperature for something simple, like an air coil inductor. The mathematics found can “loosely” be applied to more complicated parts but certainly the approach can be…

In order to design a current sense transformer you need to determine the DCR of the SEC, the inductance of the SEC, the SEC wire area/gauge to use, the magnetic area of the core, the excitation current, the % error of the CT and the desired output voltage for a given input current. Let’s start…

Transformer voltage regulation for no load and full load voltages. So you’ve chosen a bobbin, wire, PRI turns, etc… now you want to spec an output voltage under LOADED conditions and determine the SEC turns needed to meet those voltages… Your output voltage drops when the SEC is LOADED compared when it’s at NO LOAD….

Flyback Transformers, a type of switching transformer, come in two flavors, CCM (Continuous Conduction Mode ) and DCM (Discontinuous Conduction Mode). The DCM version is the one we will develop here…. The idea of the DCM flyback switching transformer is that the SEC current drops back to zero before the next ON time for the PRI. Generally a…