The core used in high frequency transformer is usually

What is the working principle of high frequency transformer?? Does it steps voltage or frequency and how it is different from ordinary transformers found in market? P.S. I could not find proper definition about H.F. transformers on web except for the calculations which made me more confused. So please tell me in lay man's words. Thank you High freguency isn't a well defined term. Most of us surely think that HF transformers are complex to design, analyze and make, because several non-idealities grow substantially as the frequency increases. For example many iron cores, which are excellent for 50Hz transformers, become awfully lossy when the frequency is only few kilohertz. Some common non-idealities (harmful or useful depending on the application): • losses in the core material • limited permeability of low loss core materials • saturation in core materials • currents through the stray capacitances of the windings (=> parasitic LC resonance circuits) • voltage loss due the leakage inductance of the windings • increased resistance of the windings due the skin effect • losses in the insulation materials • tendency of catch and spread unwanted interference The working principle of HF transformer is the same as 50Hz transformers, only the non-idealities should be taken into the account. The thinking principles (see NOTE1) "for what to use a transformer" have more variations in radio or switchmode power supply circuit design than at 50Hz. High frequency transformers are used of...

Regarding the following excerpt from a text: The text mentions that at RF air core transformers are adequate, but for 50/60Hz low freq. applications iron core needed to obtain a low reluctance. The text does not explain the reason. What is the relation between the frequency being low and the need for low reluctance medium? Low reluctance intensifies the magnetic field but why particularly at low frequencies it is needed? At high frequencies, hysterisis and eddy current losses come into play if a ferromagnetic material like iron is used a core. Hence Air core is preferred at high frequencies, despite its higher reluctance. But at low frequencies, hysterisis and eddy current losses are nullified and hence Iron core is a better choice. Way better flux-linkage and better efficiency than air core ones. \$\begingroup\$ Good question. If you look at eddy current loss equation, it has a square dependence of thickness of the material. If a core is divided and stacked into thinner plates of thickness t, with insulation in between, the sum of their losses will always be less than the loss of the core as a whole. Mathematically speaking, the sum of squares is lesser. \$\endgroup\$ It is difficult to explain in an intuitive way. But I like to think of it in terms of primary inductance. When you apply a voltage to the primary, even if the secondary is open-circuit, a certain amount of current flows in the primary, because of the primary inductance. In other words, when the secondary is ...

This problem has been solved! You'll get a detailed solution from a subject matter expert that helps you learn core concepts. See Answer See Answer See Answer done loading Question:السؤال 13 The core used in high frequency transformer is usually a) Copper Core O b) Iron Core o c) Mild Steel Core O d) Air core o السؤال 14 Flash point of transformer insulating oil should be more than a) 1000 O b) >1400 O c) 750 O d) Below 750 O السؤال 15 ? Which of the following is the main advantage of auto transformer over a two winding transformer a) السؤال 13 The core used in high frequency transformer is usually a) Copper Core O b) Iron Core o c) Mild Steel Core O d) Air core o السؤال 14 Flash point of transformer insulating oil should be more than a) 1000 O b) >1400 O c) 750 O d) Below 750 O السؤال 15 ? Which of the following is the main advantage of auto transformer over a two winding transformer a) Reduces hysteresis losses o b) Reduce eddy current losses O c) Copper losses are negligible d) Saving of copper material o Previous question Next question