GB490732A - Improvements in or relating to thermionic amplifiers - Google Patents

Abstract

490,732. Impedance networks; valve amplifying circuits. NAAMLOOZE VENNOOTSCHAP PHILIPS' GLOEILAMPENFABRIEKEN. Jan. 11, 1938, No. 957. Convention date, Jan. 14, 1937. Addition to 465,030. [Classes 40 (iii) and 40 (v)] In a wide-band amplifier for television according to the parent Specification, the anode of a valve V is connected in shunt with a twoterminal circuit comprising two circuits L1, Cl, L2 C2, tuned to the same frequency, the first having little damping while the second is heavily damped by resistance R2. According to the present Specification the need for a large value of inductance L2 is avoided by connecting it to a tapping on inductance L1. In a modification described in the parent Specification, a further tuned circuit is shunted upon the resistance R2, and according to the present Specification this arrangement is further modified by connecting condenser C2 to a tapping on the inductance of this further circuit, Fig. 2b (not shown). In a further modification, Fig. 3b (not shown), four tuned circuits are used. The tapped impedances may be the inductances, capacities, or resistance. The Specification refers to an arrangement in which the effective inductance of a coil is raised by resonance at a suitable frequency with the inherent capacity of the coil.