1E)
This circuit was found in a Popular Electronics from the 90s. The circuit generates different control signals over the same line. The transistors are from the era.
This circuit, found in documentation from the 1980s, uses an operational amplifier from that time....
This low frequency sinusoidal oscillator was obtained in documentation from the 1970s. Operational...
This circuit was found in a 1980s documentation. It is intended for remote vibration monitoring...