(under the class definition) Subject matter wherein a parallel tuned circuit consists of a capacitor of fixed capacitance value and a variable inductor, the inductance value of which may be varied over a given range in order to tune the the circuit over a range or band of frequencies.
(1) Note. To be properly classified in this subclass, the inductor must be of a variable type. If fixed inductors are switched into or out of a tuned circuit to thereby vary the frequency, classification is not in this subclass but in subclasses 56+ above.
SEE OR SEARCH THIS CLASS, SUBCLASS:
4, for tuners having an inductor which may be varied by an external magnetic field.
12+, for tuning units having a saturable core type inductor which are directly responsive to voltage and/or current variation.
38, for tuners having an inductance which is varied by winding or unwinding the inductor coil. 56+, for tuned circuits using fixed inductors which are switched into or out of circuit to thus vary the resonance frequency of the circuit.
61+, for tuners having mutual inductance variable means.
65+, for tuners where both the inductor and capacitor are variable.
SEE OR SEARCH CLASS
29, Metal Working,
602.1, for methods of making helical or wound inductance devices involving metal working and assembly.
72, Metal Deforming,
66, and 135+ for a method of or apparatus for coiling metal.
74, Machine Element or Mechanism,
10+, for drive means for a shaft operated radio tuner which may be operating a variable inductor.
174, Electricity: Conductors and Insulators,
138, for insulators, per se, upon which an inductor may be wound.
219, Electric Heating,
600+, for induction heating devices.
242, Winding, Tensioning, or Guiding,
430+, for a process or apparatus for forming an article (e.g., an inductor, capacitor, or resistor) by winding material onto a core and subclasses 118+,159+, and 600+ for a spool for receiving wound material.
323, Electricity: Power Supply or Regulation Systems,
255, and 340 for adjustable or variable inductor device systems.
331, Oscillators,
167+, for L-C type oscillators generally and subclass 181 for variable inductance tuned oscillators. See also the Search Notes under these subclasses.
336, Inductor Devices, appropriate subclass for the structure of inductor devices, per se.
338, Electrical Resistors,
283+, for zigzag or sinuous resistance elements and subclasses 296+ for helical or wound resistance elements.
