4 ms·
I remember reading somewhere that it's the highest-selling IC of all time, which is a little surprising! I'd have guessed the winner would be an op-amp of some
by ryukoposting 6mo ago
I remember reading somewhere that it's the highest-selling IC of all time, which is a little surprising! I'd have guessed the winner would be an op-amp of some kind.
555s are such delightful little guys. I used a pair of them, plus an ebay telephone line driver, to make an old telephone ring: https://hardfault.life/p/telco-2 https://hardfault.life/p/telco-2
One timer runs at the ~20Hz ring frequency, and the other runs at ~0.2Hz on a 20% duty cycle. The slow one's output feeds the enable line of the fast one, so you get 1-second burts of ringing, then a few seconds of silence, then ringing... just like a normal phone.
I moved about 5 months ago and haven't had time to get back to this project. The goal is to build a little phone company in a box, so I can have all my old PCs talk to each other with their modems.
- brudgers 6mo agoJust a guess: building an amplifier from transistors is sometimes simpler/cheaper than using an op amp. And some designs don’t need the benefit of op amps. On the other hand, building a timing circuit from discrete components is less obvious. And the 555 does so much of what often needs doing. Also, the design was not patented so they were commodity chips right away.