What components do you find superior / favorite, and why? - Page 1
Forum section: electronics / projects

author: evb149
author_rank: Regular Contributor
timestamp: November 22, 2014, 04:57:19 am
content: Code:

author: Tandy
author_rank: Frequent Contributor
timestamp: November 22, 2014, 09:15:22 am
content: The reason that so many variations of components exist is because different projects have significantly different requirements.If for example you are designing a hobby project to share with people then ideally you want to try and use widely available components that are obtainable in small quantities for a reasonable price. They may cost a little more than some lesser know products but it doesn't really make any difference to a hobbyist if a $10 project costs and extra $2 to build with readily available components. However if you are designing a mass market device that will sell millions over its market lifetime then every penny counts, if you spend $1 per unit more than you needed to by not taking component selection seriously then you have cost yourself a $1 million.Take your example of Logic ICs you have to consider the application, if you are interfacing with 5V devices you have to select a 5V tolerant version. If your application requires high switching speed you have to select one that can perform at the speed you need. In the Logic example there will be a lifetime curve where when it is new the price is relatively high and adoption is limited mainly to applications that have a specific need for using that technology. Eventually the cost begins to fall and these newer technologies become established and mass produced making them commonly used. Then with the advent of new technologies the older ones become less popular and production is scaled back making these old technologies more expensive than the newer ones. So now unless you have a particular technical need to use one of the older technologies it is prudent to use the current mainstream product. Throughout the 80's and early 90's LS series logic was king but during the 2000s HC/HCT have been the most common.There is little point in stocking up with a workshop full of components and designing your project around components that you have had in a drawer for 5 years as things may have moved on.

author: tonyarkles
author_rank: Regular Contributor
timestamp: November 22, 2014, 06:04:34 pm
content: Quote from: Tandy on November 22, 2014, 09:15:22 amI somewhat agree and somewhat disagree (this coming from a guy who will probably never use the MAX232 chips sitting in a drawer downstairs because... I've moved on from RS232 for projects). For specialty components, I totally agree that you should probably just order them on an as-needed basis. It is pretty handy though to have a bunch of "jellybean" components around that you can just build and test with. Cheap enough that you don't care a whole lot if you hook them up wrong and let the smoke out, and generic enough that they'll probably "just work".For projects that are doing "hard" things, absolutely there are probably parts that exist that will hopefully match the requirements. There's also a lot of projects and prototyping work where almost any part will do. LM324s, TL08x, 2N2222/2N3904/2N3906, LM317, etc. For me, as someone who doesn't necessarily have a whole lot of spare time to hack away on electronics projects, it's really awesome to be able to conceive of an idea for some little thing, sketch out a schematic for it, put it together on a breadboard or home-etched PCB, and have something neat working by the end of Saturday afternoon. Jellybean parts definitely facilitate that.

author: tonyarkles
author_rank: Regular Contributor
timestamp: November 22, 2014, 06:07:48 pm
content: Heh, now I'm thinking more about this.This is partly why I have a very conflicted relationship with the Arduino. On the one hand, it's crazy overpowered for a lot of projects. On the other hand, it's often not the right tool for the job at all. And on the third hand, it's sitting there on my bench, ready to get parts hooked up to it without having to order anything.

author: Tandy
author_rank: Frequent Contributor
timestamp: November 23, 2014, 12:09:13 am
content: Typically for a majority of DIY/Prototyping applications the exact part is not important. It is a shame that often shared circuit designs list very specific part numbers for example SN74HC244N that refers to the Ti part where as a majority of circuits it wouldn't matter any 74HC244 would do but inexperienced people are concerned that there might be something important about the SN prefix or the N suffix. After a while when a better understanding of how circuits work is gained you begin to realise that a variety of 74xx244 types can easily be substituted.Same with transistors, a majority of them are used for simple switching applications so as long as your circuit does not exceed any of the maximum values a wide range of transistors can be substituted.I'm not sure how you gain that confidence to substitute components in a circuit with what you have on hand. I guess it something that develops over time.