Electret microphone with a pre-amplifier

An electret microphone with a pre-amplifier is proposed for connection to a further amplifier with balanced-to-earth inputs, preferably to replace an electrodynamic moving-coil microphone in the handset of a telephone with an electronic speech circuit, its pre-amplifier comprising two voltage-contro...

Full description

Saved in:
Bibliographic Details
Main Author RALL,BERNHARD
Format Patent
LanguageEnglish
German
Published 24.10.1985
Edition4
Subjects
AMPLIFIERS
BASIC ELECTRONIC CIRCUITRY
DEAF-AID SETS
ELECTRIC COMMUNICATION TECHNIQUE
ELECTRICITY
LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKEACOUSTIC ELECTROMECHANICAL TRANSDUCERS
PUBLIC ADDRESS SYSTEMS
Online AccessGet full text

Cover

More Information
Summary:An electret microphone with a pre-amplifier is proposed for connection to a further amplifier with balanced-to-earth inputs, preferably to replace an electrodynamic moving-coil microphone in the handset of a telephone with an electronic speech circuit, its pre-amplifier comprising two voltage-controlled current sources, the respective control input of which is connected to one of the two electret microphone terminals. The balanced-to-earth outputs of the microphone are powered by the further amplifier, in particular by the balanced-to-earth microphone terminal of the electronic speech circuit. Depletion-type field-effect transistors in a differential amplification circuit are proposed as current sources, the handset terminal which is connected to reference potential being provided as a return line of the two voltage-controlled current sources (field- effect transistors), in particular when the microphone in the handset is used.
Bibliography:Application Number: DE19843413145