Of shape, ferrite material, bobbin weight and size. There are a large number of ferrite cored coil bobbins available. NOTE (3): Intermediate crossover inductor values can be supplied to order, priced at the next higher inductance value. NOTE (2): All DCR values are calculated values based upon wire length and diameter. This information is provided for reference. NOTE (1): The wire used for the coil winding is specified both in wire diameter and cross-sectional area, otherwiseĪbbreviated to CSA. Types F and G use large sized Bobbins and depending upon wire gauge can be targeted at High inductance values OR Type E, FBE3050, FBF3556 and FBG6256 Medium power Bass and Tweeter crossovers to 100w rms max. Type C: FBC2535 Medium power Bass and Tweeter crossovers to 80w rms maximum system power. Type B: FBB2728 Low power Bass and Tweeter crossovers to 50w rms max. Type A: FBA1823 Small value Inductors for Tweeter frequency modifications / tweeks. Six sizes of Ferrite Cored Coil Bobbins are offered and suitable for winding custom value crossover inductors High power handling and low DCR values.Ělternatively, smaller diameter wires offer higher inductance values but with an increasedĭCR due to the increased length of wire used.Īll crossover inductors are wound to order and can be supplied to custom values Thick 1.3mm diameter wire wound on large ferrite bobbins provide for Ferrite Inductors are available in six different bobbin sizes which,Īlong with selected wire diameters, allows for the best optimisation of your crossover board layout. Through to custom wound inductors for speaker projects. These range from air-core and ferrite coil bobbins Selection of crossover inductors and coil bobbins for loudspeaker projects. Review and buy your crossover inductors here. NI (maximum) = 0.80 x H x le = 62.Crossover Inductors and Coil Bobbins for Loudspeakers Article: Crossover inductors Part 1 Article: Crossover inductors Part 2 Maximum allowable H = 25 Oersted (from the graph above) Beyond this level, inductance drops rapidly.Įxample: How many ampere-turns can be supported by an 0R42213A315 pot core without a reduction in inductance value? They show the maximum allowable DC bias, in ampere-turns, without a reduction in inductance. The above curves represent the locus of points up to which effective permeability remains constant. Make sure the wire size chosen will support the current and fit into the core set. For the following AL values the number of turns required is:Ī L = 400, N = 16 A L = 300, N = 19 A L = 250, N = 20 Some choices based upon an LI² value of 6.4 millijoules are: There are many ferrite cores available that will support the energy required.Īny core size that the LI² coordinate intersects can be used at the A L value shown on the chart.ħ. Example: If I MAX = 8 Amps L, inductance required = 100 μHenries Required inductance L, core size, and core nominal inductance (A L) are known.ĥ.
Any core size line that intersects the LI² coordinate represents a workable core for the inductor if the core’s A L value is less than the maximum value obtained on the chart.Ĥ. This represents the smallest core size and maximum A L at which saturation will be avoided.ģ. Read the maximum nominal inductance, A L, on the Y-axis. Locate the LI² value on the Ferrite Core Selector chart below.įollow this coordinate in the intersection with the first core size curve. I = maximum DC output current + 1/2 AC RippleĢ. L = inductance required with DC bias (millihenries) Only two parameters of the design applications must be known: One can determine the smallest core size, assuming a winding factor of 50% and wire current carrying capacity of 500 circular mils per ampere. These core selection procedures simplify the design of inductors for switching regulator applications. By adding air gaps to these ferrite shapes, the cores can be used efficiently while avoiding saturation. For switching regulators, power materials are recommended because of their temperature and DC bias characteristics. For other inquiries regarding inductor design with Magnetics ferrite cores, Contact our Applications Engineers or submit a Custom Inductor Design request.įerrite E cores and pot cores offer the advantages of decreased cost and low core losses at high frequencies.
The following design guide may also be downloaded as a PDF. Inductor Design with Magnetics Ferrite Cores
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