This 555-based circuit was found in the August 1976 issue of Radio Electronics magazine. The tone frequencies are provided by the capacitors connected to the 555 IC.
This circuit was found in a Signetics documentation from the 1980s. The integrated is a PLL and...
This two-channel wired intercom was found in the April 1990 issue of Radio Electronics magazine....
The output voltage of the circuit shown in the figure is approximately 7.0 V for a 15 V supply...