EEVblog 1746 - The 555 is 55 Years Old!

Hi. Probably the most classic chip in all of electronics history. The triple 5, the 555 timer is 55 years old this year or thereabouts. So, we're going to celebrate this milestone by releasing this video on May the 5th. Let's call it from here on out International Triple 5 time a day. And yes, I'm probably going to release this at 5:55 p. m. today. And hopefully this video is going to be 5 minutes and 55 seconds long. So brief history, the triple 5 was developed in 1971 famously by the legend Hans Kemans in who was actually a contractor at Signetics at the time. So this was originally a Signetics product. He was full-time there, but he wasn't that happy. So he went to be in a contract. He was getting paid a pittance, but he had this idea for a timer chip because I guess there weren't any timer chips available back then. And that was based on a circuit that he had for uh some PLL, some phase lock loops he was working on at the time. That was the uh timer source for the PLL. So he took that idea, told Signetics about it. Hey, I want to make this timer chip. Apparently a lot of the management said, "Well, what do you want a timer chip for? " But marketing said, "Oh yeah, I think we can sell a timer chip. " So he was working for a pittance at the time in a back alley uh shop that is still there. It's a real estate agent now, apparently. So sometime in mid 1971 he uh taped out the first version of the triple five timer. Back then there were no CAD tools. You have to uh like hand cut uh the ruby lith material for the mask and everything. Anyway, it worked. But that original version actually needed nine pins. So he redesigned it and in October 1971 we get what we know and love today, the 8pin DIP triple 5 timer, the classic. And the design of it basically hasn't changed since. Although there's a new cos variant of it which gets around some current shootute limitations on the bipolar output and current consumption. But anyway, it's still going strong and still selling in the squillions 55 years later. It's available from everyone. In fact, they Signetics actually didn't bother to patent the thing back then. So, in 1972, there were already a dozen different suppliers of the triple 5 timer. Oops. But that led to its popularity. And it's still used in absolutely everything. You can even get a space rated variant of it. So, it started being shipped and cloned in early 1972. And I dug out of my archives the first mention of it that I can find in electronics Australia, November 1972. So, even before the internet, this thing had already made it to Australia. and was being advertised. Look at this. The timer of a,01 uses. And this is an ad from Signetics. And look, even like in the year of its release, they're talking about being a true standard. Um, it's and a,01 uses. Even back then, they're talking about this thing being an industry standard and the timer chip. It's just unbelievable. Anyway, this was a local dealer in Australia. So, I just find that amazing. By the year of its release, it was already they're pushing it. Marketing were pushing it as the standard chip. Uh cheapest chips down here, rock bottom cost. But the marketing just didn't die out. Everyone started using it and it became the de facto industry standard timer almost right away. And the marketing manager at Signetics, Art Fury, he's the one who actually named it 555. And yes, I don't care what anyone says, the five three 5k resistors in the circuit. That's not a coincidence. Damn it. Oh, look. Australia actually used to make 7400 series chips right here by Phillips. Unbelievable. What happened? Behold my killer oneshot circuit. I've got a classic triple 5 on oneot uh timer. I've got an indicator LED on the output here. Uh and I've got a capacitor uh which will trigger the thing when it immediately uh turns on. And I've got an RC time constant here of around about 5 seconds. So the LED once we apply power should turn on for about 5 seconds and then after that um I'm not sure. Uh we may only get one shot at this. I'm powering it from 15 volts. Uh here we go. It's doing the business. No worries. Whoa. 330 milliamps. Um almost 5 watts. Oh. Oh no. It's turned into a flashing circuit. Um and uh yeah, it went to zero. Uh so let me just uh turn the power off here and uh see if we can repower that, shall we? Will it work again? Uh no, it's dead. Can we have a hardy salute for that triple five timer? It worked a treat for 5 seconds. It did its job. Damn it. So, here's the Davecad schematic for my killer oneshot. It's a standard uh oneshot timer, but instead of having the uh timing resistor between pins seven and eight, I've actually tied pins seven and eight together and put the timing resistor here. And then our timing RC circuit charges straight away like this. And as soon as it reaches the threshold voltage, that 2/3 point, uh, the discharge transistor open collector jobby turns on and w dead crowbar short right down to ground. Anyway, try it at home. The killer one shot winner chicken dinner. Catch you next time.