This circuit for audio applications was found in an English magazine from the 80's. The circuit has a pass band below 3 kHz making it ideal for telecom applications.
This 1-transistor reflex receiver was found in a 1963 publication. The coil is for the mid wave...
Found in a European magazine from the 90s, this circuit emits beeps that are several seconds apart to...
This interface or shield circuit for instrumentation was obtained in a publication from the 90's....