This oscillator that generates signals below the audible range (sub audio or infrasound) was found in a 1965 documentation. Transistors are for general use.
This low frequency oscillator with an operational amplifier of type 741 has adjustment of the mark...
This circuit was found in a Popular Electronics from the 90s. Transistors are general purpose...
The AT21CS11 memory device offers an extended voltage range to accommodate lithium-ion battery...