GB507655A - Inductive coupling and regulation of coupled electrical oscillatory circuits - Google Patents

Abstract

507,655. Transformers; coupling coils. MICHAELIS, E. Sept. 15, 1937, No. 25094. Void. Convention date, Sept. 15, 1936. [Class 38 (ii)] In inductively coupled oscillatory circuits the coupling is adjusted without effecting detuning by movement of a magnetic dust core in relation to the windings. The coils 2, 3, Fig. 1, of a back-coupled oscillator for example may be mounted on an insulating former 1 within which the whole of the core 4 or a part thereof is so moved in relation to the windings that any detuning arising from change in coupling is compensated by change in self inductance of the coil 2. In a modification in which a part only of the core is moved to effect a change in coupling, Fig. 3 (not shown), the remaining part is independently movable to serve as a " balancing pin." Fig. 4 shows the invention applied to a frequency filter of adjustable band width in which the coils are mounted on fixed cores 11, 12 and the movable part 14 is adjusted laterally. In an alternative arrangement the fixed cores are axially bored to receive independently and axially movable core parts. Fig. 6 shows another form in which movable core parts 14, 15 are mounted for rotation with respect to fixed parts 11, 12 carrying the windings.