O core transformer

The appearance of o core transformer looks like a ring, and the cross section of o core transformer is round, this is different from toroidal transformer. O core has no sharp corners, that means less flux leakage compared to toroidal transformer. The MLT of o core transformer is short and it is copper saving. In some aspect, I think O core transformer has the advantages of both toroidal transformer and R core transformer. An O core transformer can bring dramatic improvement for your audio system.

O core transformer

High efficiency

O core has no cut, no break point, and O core transformer has a round cross section, which reduced the copper length of each turn (low DCR for each turn). So o core transformer has high efficiency.

Low flux leakage

O core transformer is a kind of nearly perfect transformer. The cross section of O core has no sharp corners, it is copper protective and a ring like core can shorten the flux path, which can make the copper wire embrace the core tightly.

O core

Hi-B oriented silicon steel sheet, thickness 0.23mm, 0.27mm, 0.30mm would be adopted. O core with closed magnetic path has less flux leakage, which make sure it has the most advanced magnetic performance. With the help of loop wire winder, O core transformers can be manufactured quickly. We have various kinds of material, which can guarantee the different needs of our customers.

O core
ofc copper wire

Copper wire

OFC(Oxygen Free Copper) copper wire applied in our O core transformers, OFC has no hydrogen embrittlement, and has a high conductivity. It is commonly used in audio equipment, vacuum electronic components, wire and so on.


From picking up a core, calculating an appropriate copper wire to delivery test, every single O core transformer should undergo very strict processing flow. Only strict processing technics can guarantee a high quality O core transformer. And only transformers from regular manufacturers can guarantee strict processing technics.

O core transformer winding

O Core Transformer Series

Power(VA) Height(mm) Diameter(mm) Weight(kg)
10 23 72 0.43
20 26 80 0.56
30 28 83 0.71
40 30 89 0.86
50 33 96 1.00
80 35 102 1.30
100 37 108 1.50
120 39 116 1.90
150 41 120 2.20
200 45 128 2.80
250 49 136 3.00
300 50 143 3.20
400 54 150 3.60
500 57 158 4.50
600 59 165 5.60
800 62 175 6.50
1000 66 185 7.60
1500 75 200 9.80
2000 80 216 12.30
O core transformer dimensionO core transformer center potted

Custom service

We supply O core transformer custom service to satisfy special requests and needs. Please get in touch with us through the contact information on our website. We can design and manufacture transformers suitable for you.