construction of Choke coil

Chokes used in radio circuits are divided into two classes - those designed to be used withaudio frequencies, and the others to be used withradio frequencies.Audio frequencycoils, usually called A.F. chokes, can haveferromagneticironcores to increase their inductance. Chokes for higher frequencies (ferrite chokesorchokebaluns) haveferritecores. Chokes for even higher frequencies have air cores.Radio frequencycoils, (R.F. chokes), usually don't have iron cores. In high power service so much heat would be produced in making and destroying the field in the core that the coil would burn up.