takao21203
- Joined Apr 28, 2012
- 3,702
btw the thick wire isnt good since you have a gap between the wire and the ferrite, just saying.
Some of the reasons ferrite toroids in power supplies heat up is that it takes energy to swing the magnetic field back and forth, and depending upon how the core is being used some or all of that magnetizing energy is lost.< Some text removed for clarity>
Question: why do the large toroids from a switchting power supply heat up considerably?
when the resistance should be 0.02 Ohms?
< Some text removed for clarity>
thats why you dont get the DC resistance, one of the reasons, besides that 0.02 ohms = absurdSome of the reasons ferrite toroids in power supplies heat up is that it takes energy to swing the magnetic field back and forth, and depending upon how the core is being used some or all of that magnetizing energy is lost.
In the case of a continuously changing magnetic field, eddy currents are induced in nearby conductors. Some ferrites have significant conductivity but the greatest part of the eddy current losses occur in the cross section of wires close to the surface of the magnetic core. That's why several parallel strands of fine wire or copper strips are often used instead of large gauge wire.
Hi,
I'm trying to build a broadband transformer (1-300kHz) to convert an input impedance of ~20mOhm to 100 Ohm, that's 1:5000.
I thought I'd take a toroid and make 1:70 turns. But beyond 10 secondary turns there is no more gain in impedance/voltage.
I'm using an epcos N30 (µ=4300) toroid.
What am I doing wrong? Do I need a different core material? Do a need a different core type (binocular?)? Do i need more primary turns? is it even possible with a single transformer?
Thanks
This is not good advice, power is normally scarce at the receiver and it normally pays at least to be aware of how much you are discarding by poor antenna matching. It may be a design decision to be wasteful, but it is rare that it is overlooked.Who worries about radiation resistance on a receive antenna.
by Jake Hertz
by Jake Hertz
by Aaron Carman
by Aaron Carman