The Texas Instruments LED digital watch, introduced in September, 1975, transformed the digital watch from a costly curiosity that even appeared in a James Bond movie to a mass market item which would soon devastate the Swiss mechanical watch market. LED displays were power hungry, so LED watches required pushing a button to display the time—otherwise the battery would quickly be depleted.
Here, Curious Marc uses a rare packaged Texas Instruments watch chip and vintage Hewlett-Packard “bubble” LED displays from the 1970s to assemble a vintage clock and discovers that ancient integrated injection logic chips were particularly finicky about their power supply and logic level voltages.