(under the class definition) Subject matter wherein some resistance value is built into or adapted to be inserted into or removed from a tuned circuit to thereby vary the "Q" or damping of the circuit.
(1) Note. The sharpness of the resonance or sensitivity of a tuned circuit is determined by the ratio of energy stored to energy dissipated, hence is directly proportional to the reactance in the circuit and inversely proportional to the resistance. This ratio of stored energy to dissipated energy is called the "Q" of the circuit.
(2) Note. The resistance of the tuned circuit does not have to be of the variable type but may be a fixed type resistance. The resistance must, however, be more than the inherent load resistance presented across the circuit when the circuit is connected to a load.
SEE OR SEARCH CLASS
333, Wave Transmission Lines and Networks,
173, for wave filter networks that may utilize ohmic resistance elements for controlling the selectivity or frequency band width of the network.