| This circuit produces a ringing sound similar to that made by more recent telephones. It consists of three almost identical oscillators conn...
| This circuit produces a ringing sound similar to that made by more recent telephones. It consists of three almost identical oscillators conn...
| Here is a very simple, inexpensive and interesting project which provides lot of fun to a home experimenter or hobbyist. This simple transmi...
| This simple circuit will tell you, by sounding a buzzer and flashing a LED, that a telephone line is in use. If the telephone line is free,...
| The circuit in the diagram was originally designed to monitor an oscillator, but can also be used as a general-purpose level indicator f...
| Alan G Hobbs 18telephone-bell simulator This circuit is intended for use in a small private telephone installation. The ringing tone sequenc...
| xylophone elektor december 1980 — 12-09 With Christmas practically on the doorstep, small, sound producing circuits become very popular. T...