The circuit shown with the LM3914 was found in the March 1992 issue of Radio Electronics magazine. The circuit has a full-scale adjustment.
CTS IoT Quartz Crystals Available through Mouser Electronics, CTS quartz crystals are especially suited...
This circuit is from a 1969 Electronics World. The transistors may be modern general-purpose...
This circuit is from 1967 General Electric documentation. It uses SUS which are not very common...