Circuit of Telephone with Increasing Volume

Published:2011/7/8 0:40:00 Author:Joyce | Keyword: Telephone , Increasing Volume | From:SeekIC

The circuit of telephone with increasing volume is an auxiliary device attached to the telephone externally, which would produce the needed bell signal, while the bell ring sent by telephone lines works only as the control signal of the circuit . In this circuit, the bell signal is generated by the multivibrator composed of gate circuit CD4069, and the amplification and output of the volume of oscillator is controlled by a field effect transistor through its transconductance of the change of Gm. And the change of the Gm is realized by the times of bell ring sent by telephone lines going through CD4017`s shift function. The composition of the circuit is as shown.



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