Iron Powder Cores

Home Alarm System RFI Kit

RFI-3 Home Alarm RFI Kit

This RFI-3 kit is specifically designed to cure most alarm systems triggered by Radio Frequency Interference problems. The kit contains ferrite toroids (“Donut” shaped ferrites) including a snap on ferrite for AC power supply protection and smaller toroids for alarm sensor lines selected to eliminate RFI from 1 to 1000 MHz. The ferrites are easy to use, don’t require modification of the protected equipment and work in almost all cases.

IRON POWDER TOROID CORES-xx

Iron Cores 150x150 - Iron Powder CoresIron powder cores are more stable than ferrites and do not saturate as easily so they are best for tuned circuits, filters, and high power inductors. They come in different “Mixes” for use at different frequencies. For best “Q” use the Mix specified for your frequency.To find the number of turns to give the desired inductance for your coil use the formula below:

 

Turns = 100 x iron core formula 300x14 - Iron Powder Cores

Toroid Dimensions

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To order specify core size and mix (e.g. T200A-2). Available in sizes that have µH per 100 turns shown in table.

All iron powder cores are special orders.  Please allow one week for shipment after order received.

The iron powder cores shown in the above tables are primarily used for either high power feed line chokes for common mode current reduction or for 4:1  and 9;1 very high power transmission line transformers.

For high power feed line chokes, choose the inside diameter of the iron powder core closest to the transmission line outside diameter and use 6-20 cores at the junction with the antenna feed.

For 4:1 (50/200 or 75/300 ohm) transmission line transformers in the range of 1.8-30 Mhz, select the size appropriate for the power level as follows:

T200A x 2 = 1.5KW

T300A x 2 = 2.5KW

T400A x 2 = 5KW

Use Mix 2 for all the above transmission line transformers.  Fully assembled and enclosed units are available for each of the power levels.  Click HERE for information.

4:1 transmission line transformers using iron powder cores are typically used for ladder line to 50 ohm coax connections

For .1 – 2 Mhz wide band transformers use Mix 26 which has a higher permeability and requires less turns to achieve a given inductance. Mix 2 has almost constant permeability from 1-30 Mhz.  Mix 26 has an initial permeability of 75 at .1 Mhz and gradually decreases to about 10 at 30 Mhz.  For high power AM broadcast range (.5-1.7 Mhz) transformer, use Mix 26 to reduce the turn count.

Minimum order for iron powder cores is $50  

Shipping on larger cores in quantity may be more than $10 – email/call for quote.