Go Down

Topic: how do I wire a 74ls74 d type as a flip flop? (Read 6196 times) previous topic - next topic


It worked correctly on the first test (15 minutes before the drop dead deadline) .(I worked 27 hours straight through to finish it)
The connections always worked! Why did they work in such a noisy net - I thought a lot; but, I could never figure it out. Old days memoirs bring nostalgia! People want to go back - make it again; but, in vain.....!

6802 Microprocessor Learning System (wire-wrapped in 1988, worked and helped learning 6802. The
keyboard is misplaced)


Apr 10, 2017, 08:25 pm Last Edit: Apr 10, 2017, 08:36 pm by raschemmel
The 20 gauge solid wire I used made a very snug fit in the breadboard. Most people use 22 gauge solid. I used CMOS chips to drive the signal that had to travel at least 100 feet to the darlington transistors that drove the neon lights. I think soldering has a higher chance of failure due to the possibility of a cold solder joint (admitedly rare if done by a professional, but still possible). I used a breadboard because there was no time to build a soldered controller. Most of my time was spent building the fountain controller. (I have photos but I'm not sure you're ready for those but I'll post them if asked.)


Apr 11, 2017, 05:48 am Last Edit: Apr 11, 2017, 05:55 am by GolamMostafa
cold solder joint
Oh raschemmel! You are talking about cold solder joint. It had already gone from my memory. Back in 1992, I had to fly from the desert land of Oman to Schlumberger Research Center at Houston for taking Training on 'Soldering'. I know out-and-out the terrible shock came down to the fate of an Instrument Engineer when the electronics logging tool failed downhole at temperature =>2000F mainly due to cold solder.

In the great event of your art performance, you certainly was right not to go in the soldering business. High power flow would certainly generate huge heat and would melt the joint creating a great fiasco. I admire your right decision taken at that time.   

Now-a-days, people have access almost to everything ready-made of the desired quality. New generation, new experience, new world-view, and many new things! But, still the role of 555/74LS74 could not be ignored. These are the basics; they push us through SSS methodology for the creation of a big ting from the scratch.
(I have photos but I'm not sure you're ready for those but I'll post them if asked.)
It would certainly be matter of great great pleasure to see the pictures. Please, post them.

Sharing another experience with the mates:


Apr 11, 2017, 03:52 pm Last Edit: Apr 11, 2017, 04:01 pm by raschemmel
It would certainly be matter of great great pleasure to see the pictures. Please, post them.
You asked for it.

Tribute -82 Fountain Controller (Controlled 43 miniature water pumps mounted on a frame at the bottom of a large satelite dish decorated with stained glass leaves (fountain design and construction by Sam Salde)

If you look closely you'll see every board has leds on it. The party event took place in Paramount Studios Sound Stage 13 (the studio used to make the FIRST STAR TREK MOVIE). It is a 200 foot sound stage with catwalks on both sides. The criteria for the project was a controller that could be debugged in a dark room in the event of any malfunction. (Thank god that wasn't necessary)

The blue wires are on the top of the board because they are the rugged 20 guage wire used for the lighting controller. This was because another criteria was the controller withstand a drop test in the event one of the roadies dropped in during unloading or if the truck hit a bump. The wires go through through holes pads and are soldered on the bottom. (no wire came loose)

Go Up