This is the circuit of a commercial radio sold in Japan in the 1960s. The IF is 455 kHz, and the supply is made with a voltage of 9 V. The radio receives stations in the medium wave range.
This simple alarm circuit was found in a 1998 documentation. When the sensors are activated, the...
This circuit was found in an old American documentation. The integrated circuit used is uncommon...
Found in a 90s Electronic Design, this suggestion to have a higher voltage in a fixed regulator...