EEVblog

EEVblog 1746 - The 555 Is 55 Years Old!

EEVblog’s episode 1746 marks the 555 timer’s 55‑year milestone, releasing the video on May 5 at 5:55 p.m. and aiming for a 5‑minute‑55‑second runtime to echo the chip’s “triple‑5” moniker. The timer was invented in 1971 by Hans Camenzind, then a low‑paid contractor at Signetics. After a hand‑cut mask produced a nine‑pin prototype, the design was refined to the now‑familiar eight‑pin DIP in October 1971, a layout that has changed little despite later CMOS versions that improve current handling. Signetics didn’t patent the device, so by 1972 a dozen firms were already cloning it, cementing its status as an industry standard. The video’s demo—a “killer one‑shot” circuit that burns out after a 5‑second pulse—illustrates both the chip’s robustness and its quirks, while a space‑qualified variant underscores its longevity. The 555’s simplicity, low cost and universal availability keep it relevant across hobbyist projects, commercial products and aerospace, demonstrating how a well‑engineered analog block can dominate for decades and shape design education.