This analog frequency meter for low frequencies was found in Radio Electronics magazine from July 1958. The circuit has several scales with the frequencies indicated in the diagram.
Found in a 1968 Mullard manual, this circuit measures temperature by infrared radiation. The...
Found in a 1970s RCA documentation, this circuit generates signals according to the component...
This Harris circuit from the 90's is intended for recording old EPROM memories. The circuit uses...