This is one of the first radios with an integrated circuit. The circuit is from a Radio Electronics from November 1969. The circuit is powered by a 9 V battery.
This 200 kHz oscillator was found on a 90's EDN. It consumes only 2.8 mW and has CMOS compatible...
Although we found this circuit in an old documentation from the 70's it can still be assembled with TTL...
This audible continuity test was obtained in a book from the 90's describing simple projects. The...