Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
GB9067/47A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
STC PLC
Original Assignee
Standard Telephone and Cables PLC
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Filing date
Publication date
Application filed by Standard Telephone and Cables PLCfiledCriticalStandard Telephone and Cables PLC
Publication of GB648382ApublicationCriticalpatent/GB648382A/en
H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
H03F3/50—Amplifiers in which input is applied to, or output is derived from, an impedance common to input and output circuits of the amplifying element, e.g. cathode follower
H03F3/52—Amplifiers in which input is applied to, or output is derived from, an impedance common to input and output circuits of the amplifying element, e.g. cathode follower with tubes only
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Engineering & Computer Science
(AREA)
Power Engineering
(AREA)
Amplifiers
(AREA)
Abstract
648,382. Valve amplifying circuits. STANDARD TELEPHONES & CABLES, Ltd. April 3, 1947, No. 9067. Convention date, April 10, 1946. [Class 40 (vi)] A positive bias potential for the cathode of a thermionic valve amplifier is provided by a second valve connected between the cathode of the amplifier and the H.T. source and provided with a negative feed-back coupling between its anode and grid operative at signal frequencies. The anode of one section 8 of a double triode valve is connected to the cathode of an amplifying section 4. Negative feed-back for the section 8 is taken from the junction of condenser 13 and resistor 14 connected between the anode and cathode of the section. This arrangement ensures that the A.C. resistance of the cathode impedance of the amplifier section 4 is much lower than its D.C. resistance, thus minimizing unwanted negative feed-back.