This circuit was found in the October 1983 Radio Electronics issue. It is applicable to old analog telephones. The circuit uses common components.
This sensitive medium wave (MW) radio pick up the local station without the need of an external...
This audio circuit was published in a Rado Electronics issue from October 1963. The transistors are from...
Using a V/F converter this circuit was found in the June 1991 issue of Radio Electronics magazine. The...