Winding Chokes

Radio Record, Volume IV, Issue 29, 30 January 1931, Page 15

Winding Chokes

YELLULOID formers for radiofrequency chokes have previously Leen described in the "Radio Record," but slight alterations have been made in the dimensions, and as this type of broadeast choke has _ proved _ itself highly efficient, a brief description is given here. Stout celluloid should be used, and may be marked out: by placing over

the printed diagram, scratching the lines with a sharp steel point or strong needle. If the scratching . is. -deep, much of the shape may be broken out of the sheet by bending the celluloid. Two pieces the size shown are required for each choke, One of these is then livided down the centre and one piece attached to each side of the full piece with celluloid cement. ' Hnd pieces’ are then put on, larger than required, and when all is set, they ean be trimmed with scissors. A hole -in one of the angles at each end will allow the insertion of a meccano spindle for winding, otherwise the winding may easily be done by hand. "One thousand turns of 86 or 388 enamelled wire is put on, 200 turns in each set of notches, The ends are passed through two holes and fastened with cement, or holes may be drilled for the ‘insertion of bolts to act as terminals. \-Two holes ‘in the base provide for ' serewing to the baseboard. The direct current resistance of these chokes is 40 ohms with 36 wire and 63 ohms with 38, so with only a few mils passing the drop is less than one volt.