Subminiature Transformers and their Application to Junction-Transistor Circuits
E. Dunkin, Denis L. Johnston · IRE Transactions on Component Parts · 1955
The technical limitations of subminiature audio or control frequency transformers or inductors are discussed and some features of their design described. Statistical methods are used to control quality and specification limits as the physical sizes are too small to allow for individual adjustment. A miniature toroidal-shell construction has given results comparing favorably with laminated assemblies below a certain size and in this form, optically-finished lapped joints are employed in the magnetic circuit. The use of subminiature core assemblies as transductors has also been investigated.