Pot cores are available in a wide range of sizes with adjusting screws. Typical adjusting range is 15% with some as high as 30%. Pot cores with small gaps provide the largest range. Pot cores with large gaps have a smaller adjustment range; but, provide the best resolution and long term stability. Compared to pot cores without adjusters; adjustable pot core inductors may result in a lower Q. This is due to the high flux density in the adjuster which results in increased core loss.
Various core and winding configurations can provide inductance adjustments for both power and signal level requirements. Simple saturable reactors and more sophisticated magnetic amplifiers are examples of power applications. For signal applications, pot cores offer a simple and economic solution, especially for inductance values down in the micro-henry and low values of milli-henries. Designs can either be made to adjust from 100% to 30% down; or, very small percentage changes with relatively linear characteristic. Frequencies can range up to low mega-hertz range.