GB986424A - Improvements in or relating to amplifiers - Google Patents

Improvements in or relating to amplifiers

Info

Publication number
GB986424A
GB986424A GB1365461A GB1365461A GB986424A GB 986424 A GB986424 A GB 986424A GB 1365461 A GB1365461 A GB 1365461A GB 1365461 A GB1365461 A GB 1365461A GB 986424 A GB986424 A GB 986424A
Authority
GB
United Kingdom
Prior art keywords
transistor
amplifier
collector
gain
potential
Prior art date
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
GB1365461A
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.)
EK Cole Ltd
Original Assignee
EK Cole Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by EK Cole Ltd filed Critical EK Cole Ltd
Priority to GB1365461A priority Critical patent/GB986424A/en
Publication of GB986424A publication Critical patent/GB986424A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03G—CONTROL OF AMPLIFICATION
    • H03G3/00—Gain control in amplifiers or frequency changers
    • H03G3/20—Automatic control
    • H03G3/30—Automatic control in amplifiers having semiconductor devices
    • H03G3/32—Automatic control in amplifiers having semiconductor devices the control being dependent upon ambient noise level or sound level

Landscapes

  • Control Of Amplification And Gain Control (AREA)

Abstract

986,424. Automatic volume control circuits; transistor gain control circuits. E. K. COLE Ltd., and J. A. JACKSON. April 9, 1962 [April 15, 1961], No. 13654/61. Headings H3T and H4R. In an automatic volume control system the variation of collector resistance with base current of a transistor operating below the knee of the collector current-collector voltage characteristic is used to control either the signal level fed to an amplifier or the amplifier gain. Fig. 2 shows the audio stages T1 and T2 of a transistor car radio, negative feedback being applied from the secondary of the output transformer OT to the emitter circuit of transistor T1 via a control circuit incorporating transistor T3. The collector impedance of T3, which forms with resistor R6 a potentiometer across the audio output, is controlled by a potential applied to the base via the terminal B, the potential being derived from a source dependent on the speed of the engine, so that as the engine speed increases the collector resistance of T3 decreases, reducing the feedback voltage and increasing the gain of the amplifier. The D.C. potential for transistor T3 is obtained by rectifying the audio output of the amplifier with diode D.
GB1365461A 1961-04-15 1961-04-15 Improvements in or relating to amplifiers Expired GB986424A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB1365461A GB986424A (en) 1961-04-15 1961-04-15 Improvements in or relating to amplifiers

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB1365461A GB986424A (en) 1961-04-15 1961-04-15 Improvements in or relating to amplifiers

Publications (1)

Publication Number Publication Date
GB986424A true GB986424A (en) 1965-03-17

Family

ID=10026967

Family Applications (1)

Application Number Title Priority Date Filing Date
GB1365461A Expired GB986424A (en) 1961-04-15 1961-04-15 Improvements in or relating to amplifiers

Country Status (1)

Country Link
GB (1) GB986424A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2438376A1 (en) * 1978-10-05 1980-04-30 Thomson Brandt Sound level control for motor vehicle radio - uses control signal generated by ignition coil contact breaker terminal to increase level with increasing speed

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2438376A1 (en) * 1978-10-05 1980-04-30 Thomson Brandt Sound level control for motor vehicle radio - uses control signal generated by ignition coil contact breaker terminal to increase level with increasing speed

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