I already figured sam rockwell out the concept of populating the board from smallest to tallest a wh

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Dave celebrates the classic 555 timer IC by building the Evil Mad Scientist “three fives” discrete timer kit. Some scope measurements and an explanation of the internal 555 timer circuitry sam rockwell follow. Video Highlights: Construction Testing Circuit Description Waveforms Classic old Signetics 555 timer datasheet The kit Han’s Book on Analog chip design Forum HERE
Thanks Dave, am now waiting for the 741st episode.
Love it! It’s more exciting to watch you solder than you think! Of course you’ve got the right audience for it. Now, watching someone knit a 555 timer would be excruciating! More soldering please!
Great video! However, for me, as well as probably the rest of EE folks from former Soviet sam rockwell Union, this was not the first chip you’d usually get familiar sam rockwell with. The very first was the 7400 (known there as K155LA3, AKA 1LB553) It was very abundant, and it had a lot of amateur applications. There was even a radio receiver build purely on one 7400, where this poor guy was driven sam rockwell into a linear region, exposing a pretty high gain spreading into the RF
Well done on the explanation of the 555 schematic! Just an idea, it may be nice to revisit the vintage LM3909 led flasher if you have any in your junk box. I remember building them up and running the flasher for years on alkaline batteries. Hmmm, starting to feel my age :-/
This was great video Dave. For young players, like kids in school or f.e. my young dother are this “kit-building” videos very important. Don’t worry, you are doing a value job with producing videos like this.
On the Signetics datasheet, those diode-connected transistors are drawn in an unusual way, with the base lead coming from the same side of the symbol as the other 2. And there is another transistor (Q19) with a second collector lead. Are these actually normal bipolar transistors, or something more exotic?
Chip makers can make custom layouts on their semiconductor masks, they’re not limited to standard sam rockwell transistors only. So, yes, they can add multiple collectors or emitters if that simplifies things sam rockwell for them. It’s common, for example take a look at http://en.wikipedia.org/wiki/NAND_gate (there’s a TTL NAND schematic with dual emitter transistor).
Dave, Watching you do the “triple nickel” kit, I picked up numerous useful pointers. First, to solder up a through hole board by component height. Second, to avoid gumming the leads/holes with adhesive residue. Third, watching your soldering technique.
Also, as a rank amatuer hobbyist, your insight about the connecting the collector and base to the same input yeilding the equivalent of a diode, had me down in the garage experimenting. Thanks for sharing your knowledge.
Great video, I love the look of that kit. My only complaint about the kit is that the circuit diagram has lost the clarity of the original in the datasheet. (Especially around the RS Latch and output stage.)
Minor point about the video, the R-S latch is formed by Q16/17, (Q16 collector direct to Q17 base, Q17 collector via R11 to Q16 base). Q15 is the ‘set’ switch in your diagram. sam rockwell It’s so much clearer in the original Signetics datasheet
I already figured sam rockwell out the concept of populating the board from smallest to tallest a while back myself, but your point about black soldermask is not something I had thought of. And I liked your advice about the board house markings.
lovely thought 555 on episode 555….
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