Originally Posted By: Reddy45
Originally Posted By: y_p_w
Originally Posted By: Reddy45
Originally Posted By: mk378
That is all that a 7448 chip is supposed to do. It takes a number in binary and converts it to 7-segment output. Pressing the buttons produces a 4 bit number through the diodes.
http://www.ti.com/lit/ds/symlink/sn7447a.pdf
The 4511 is a slightly more modern version which adds a latch stage (basically 4 bits of RAM), so it is able remember the number that was last pressed, unless the power is cut off.
https://www.sparkfun.com/datasheets/IC/74HC4511.pdf
So what that board is doing, is all that it is capable of doing. And it must be correctly soldered.
Right on then! Thanks for the explanation!
Not too bad for my first PCB solder project but I definitely need to buy some thinner solder as I made a mess with this one.
What do you use these days? I'm not much with a soldering iron, but I remember doing some project in junior high school using lead/tin solder to mechanically attach metal pieces. It wasn't for anything electronic. Then the next year I took a shop class, and the teacher demonstrated how to attach a metal handle to a metal cup. I had no idea what "flux" was until he showed it. When I tried it I got maybe one in 5 parts to adhere just based on sheer luck. I had no idea that the flux was supposed to prep the surface for the solder.
I do remember trying out a soldering iron once at work because I was kind of bored. We had some part that needed to get a resistor attached to work better, and it could be just soldered in place. I had no idea what I was doing, but I had a lot of time waiting for our prototypes to come back that I did it anyways.
Most of the electronics you get these days use RoHS compliant assembly, which means no more lead. I understand that a lot of solder joints aren't done correctly to account for non-lead solder.
I use a $20 30 watt Craftsman pencil soldering iron and flux-core LEAD solder. Flows beautifully and makes strong joints!
I'm not really aiming to build anything in particular, but I occasionally need to use solder for appliance repair, and it's a great way to enhance your dexterity.
Mine was a Radio Shack soldering iron, but I was using 60/40 lead-tin solder. I don't remember the exact brand name (might have been Archer?) they used. I also only used the solder that came in the kit, but I'm pretty sure I would have had better results with rosin-core solder.
I managed to burn a bunch of tips, although the kit came with two spares. I didn't believe it, but they kind of just melted away.