This commercial receiver from the year 1958 uses two AA cells as Power supply. The circuit is intend to receive MW station and the transistors are germanium types not easy to find today.
This circuit is suitable for modulating AM transmitters. The circuit is from a 1977 radio amateur...
This double tone generator uses a specific integrated circuit, having been found in a 1977 CMOS...
This is a simple 1-digit voltmeter circuit using voltage comparators. It was found in a 2004...