Show Two Make Circuit Very Selective While a n regenerative circuit may be readily obtained by liy In Inserting a eter In the plate cIrcuIt circuit It la is not so simple a task to obtain a tickler feed teed feedback feedback back with ordinary apparatus on the tho market unless honeycomb coils colls are used There arc are of course couplers with fixed tickler windings With or- or ordinary or ordinary apparatus however the double coupler back teed circuit Is easily ar- ar arranged arranged ar arranged ranged the objections to single circuit single action are overcome o and there Is com com- complete com com- complete complete tuning in every ery circuit and any desIred degree of ot coupling between them As commonly employed the prImary switches of ot one coupler are connected to the antenna and ground as usual till II lili Scheme That GIves Fine Control of Amount of Inductance TIle The secondary of this tills coupler how how- however however ever er Is connected to the ends of ot the prImary winding of the second cou cou- cou- cou coupler coupler coupler the The switch points of the second coupler go to grid and filament lIke the usual secondary connections The secondary terminals of the second cou- cou coupler coupler cou coupler arc are connected to the plate cir clr- circuit cir circuit cult The wave length of the primary cir clr- circuit cir circuit cult Is adjusted by the switch points on the first coupler aided by the con con- condenser condenser con condenser denser In the ground circuit This variable condenser should have a ca- ca capacity Capacity ca capacity of or 23 plates The couplIng between bet een the primary and secondary Is adjusted by rotating the rotor of ot the first The secondary circuit Is tuned by the switch points on the se second ond coupler and the coupling between the see see- secondary circuit and the plate cIrcuit tickler Is adjusted by the rotor of ot this coupler The secondary of ot the second coupler acts as the plate tickler coil coll This circuit should be very selective selective selective tive and give a little better than the average sets set's results results Radio News |