This simple clock can be used to generate signals up to 100 kHz, depending on the crystal. We found it in a 1967 documentation. Note the high supply voltage.
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....