So-called article G. Bortnovsky in "Radio", 1996, No. 10, pp. 36, 37, which told about the AF amplifier connected via inductive sensor to a telephone and allows you to listen to phone calls through the dynamic head.
Young Amateur radio operator, a fifth grader Igor Kutsko out of Krichev, Mogilev region (Republic of Belarus), has proposed to significantly reduce the number of parts of such the device for applying a preset amplifier - chip CAN (Fig. 1). The volume sound sound drivers BA1 with the receipt of the input signal amplifier with inductive sensor L1 or connector X1 (United, for example, with the release of player) can be adjusted by the variable resistor R1.
It feeds the amplifier from the source, composed of two series - batteries connected 3336, six galvanic cells or network rectifier, for example adapter. With the latest version of power source should be placed as far as possible from the inductive sensor to exclude background of the alternating current in the dynamic head.
To mount the main parts of the amplifier on the circuit Board (Fig. 2) from unilateral foiled fiberglass.
Author: I. Kutsko, Krichev, Mogilev region, Republic of Belarus