Air Wound App Notes Air Wound Part No. Toroid Wound Part No. Standard Inductors Tunable Coils



PREFACE: There are many RF/Microwave applications where inductive coils need a closer tolerance than what is practical to produce.  Most of the time these coils end up being actively adjusted (“tuned”) in circuit to achieve the desired results.  The reason for this is that there is no commercially available test equipment that can be used to individually tune them.  The test frequencies and inductance ranges of virtually all of the test equipment on the market at this time are not close to these application parameters.  Tuning them “in circuit” can also be difficult as there are usually multiple elements that need to be adjusted concurrently to achieve the desired results. 

The coils needed for these kinds of applications (specifically Air Wound and Toroidal Topographies) need to be made in a manner so that efficient “tuning” is possible.  Emicon has a lot of experience making coils for this kind of application as we have been successfully making them for almost 30 years. 

Recently, having been approached by several customers, we have started working with those needing this kind of “tuning” to develop a method for individually tuning the inductive elements out of the application circuit.  This has several advantages.  The most obvious is that it is easier and quicker than doing it in the application circuit. It also follows that the end item cost is less since a high level of skill is needed to tune them in the application circuit and less is required when tuning them individually.  Our goal is to deliver “tuned” coils to the customers that eliminate this costly and time consuming process on their end.   

WHAT WE NEED TO START: In order for us to make a proposal to a customer needing “tuned” coils we need some basic information to start a dialog.  First of all we need to know the application frequency.  Is there a tolerance on frequency? If so, how much?  We need to know the nominal inductance value and the desired tolerance on inductance. Is there a power requirement?  If so, what is the maximum power level?   Is there a minimum Q requirement?  If so, what is it?  Is the inductor to be surface mount or leaded?  Is there a physical size requirement?  If it is leaded what is the lead configuration?  

WHAT HAPPENS NEXT?: Once we have all of the parameters needed to determine that we can develop a individual tuning method for the application we will write a proposal.  The proposal will include some non-recurring development costs needed to design and produce an application specific test circuit that the inductors will be tuned in.  The proposal will include producing and tuning some small initial amount of inductors in the newly developed circuit.  Also included will be an identical test circuit to be delivered to the customer that can be used by them for verification purposes.  Our goal is to basically develop this individual tuning method at cost as we intend to make our profit delivering recurring tuned inductors to the customer. 


TEL (915) 590 0795
FAX (915) 591 1404


900 Loma Verde, Suite A

El Paso, TX 79936  U.S.A.