REACTION BY CONDENSER

Evening Post, Volume CX, Issue 110, 5 November 1925, Page 11

REACTION BY CONDENSER

The writer lias recently incorporated in iiis receiver a reaction circuit df the type used in tjie. Reinartz receiver circuit ami alternatively named alter Wcagaiit. T)ic result i.s liigJily satisfuctory, and some oxperinientallyminded listeners who have not tried it may iind it interesting and use-fill. Itcan easily-be applied to-any stanclanl throß'Coil r6ti;i.vci".l»y llip uddit'iuii «f « dioko coiJ ftjacl a. varkbls coadeasei'.

The choke coil, which must be placed ■well away from the other coils in the set, and may be fastened against the back of the cabinet, may be a regular radio coil oi! about 2UO turns. It is connected between the plate of the valvo and the telephones, as the reaction coil was, and the telephone condenser should usually be removed, though this may nut be found necessary. Leaving the reaction coil connected to the plate as before, the other end is disconnected from the telephones and wired to one side of the variable condenser, which may be of .005 uifd. or .00] nifd. The other sido of tho condenser can be connected to the earth lead .or any other point at earth po\cntial, or to tho battery side of the telephones. The.reaction coil can be placed, and left, quite closely coupled to the secondary coil, and reaction ..is then increased by turning the condenser towards maximum. Experiments with reaction coils of different sizes will show thai it is possible to find a combination of cqil-aizc and position which will give almost equal reaction over a large range of wave-lengths, and this greatly facilitates the operation of the rcccivor, because any great change in the reaction adjustment usually alters the tuning con&ideiolily/'i'liis type of reaction is particularly smooth in operation, and may be to tho tasto of those who find the usual moving coil control difficult to handle.