Filter chokes
The largest values of inductance that can be obtained in practice are on the order of
several henrys. The primary use of a coil this large is to smooth out the pulsations in direct
current that result when ac is rectified in a power supply. This type of coil is known
as a filter choke
Inductors at radio frequency
The radio frequencies range from 9 kHz to well above 100 GHz. At the low end of this
range, inductors are similar to those at audio frequencies. As the frequency increases,
cores having lower permeability are used. Toroids are quite common up through about
30 MHz
Inductors at audio frequencies range in value from a few millihenrys up to about 1 H.
They are almost always toroidally wound, or are wound in a pot core, or comprise part
of an audio transformer.
Inductors can be used in conjunction with moderately large values of capacitance
in order to obtain audio tuned circuits. However, in recent years, audio tuning has
been taken over by active components, particularly integrated circuits
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toroid and pot core chokes will not work.. they can only be used in a pre determined circuit that doesnt need to be tuned.. stan is using a tunable negative choke. ruling them out. i know of two ways to make a tunable choke.. one is to finely sand a small line from end to end and use a copper rod that can slide from end to end.. the copper rod is attached to secondary neg along with neg choke.. the other way is shown on last post.. allowing your ferro rod to be adjustabe. the one in the pic would work really good for having ability of electronic control by means of servo.
outlawstc
