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icharters:

--- Quote from: techman-001 on June 22, 2019, 11:13:48 pm ---
--- Quote from: pwlps on June 22, 2019, 08:11:28 pm ---
--- Quote from: icharters on June 22, 2019, 07:37:48 pm --- I think I'm going to build a power supply to start with and see where that takes me.

--- End quote ---

Oh, another one, since I joined this forum I see so many beginners pushed to start with a power supply project, seems we are really short of ideas here   :D For me a power supply is absolutely no fun, a top most boring stuff: can't play music nor make dance some remote stuff with it,  not even a way to have some fancy display, really nothing to play to the gallery (kids/wife etc.)  >:D

--- End quote ---

A power supply is the foundation of electronics, no power, no electronics, so it makes sense to start at the beginning and work ones way up from there.

Assembling kits that look flash and impress people who don't know anything about electronics either, whilst good for stroking ones ego's isn't electronics, but it's probably art.

You may be looking for artblog.com ?

--- End quote ---

I'm inclined to agree.  Power is the basis for everything.  If I don't understand how to take power in, adapt it, make sure it's clean, distribute it, etc.  what hope do I have for doing anything else.  Also, I'm a low voltage technician by trade, and went to school for computer science (and continue to build stuff for fun), so just hooking up arduino development boards and adding peripherals and doing some light coding is not interesting as it isn't going to teach much if anything.  I want to design my own PCBs from start to finish and do cool custom hardware stuff.

I'm sure a power supply will keep me busy for a while.
rstofer:
Jameco has a nice little +-15V power supply as a kit:

https://www.jameco.com/z/JE215-Dual-Output-Adjustable-Linear-Regulated-Power-Supply-Kit_20626.html

I built it for op amp circuits but I haven't used it yet.

Note that the output is adjtable from +-5V to +-15V.

Yes, it's a kit so there is no design involved but learning how it works is useful when it comes time to power other projects.  You can fall back on the kit design as a starting point.

Power is pretty fundamental yet somehow I did without a bench PS for about 60 years.  I used batteries, fixed supplies and, lately, wall warts.
Siwastaja:
Getting off-topic, but I don't think building a "lab" power supply out of some 78xx regulators is necessarily a wise project. The reason is simple - it's not a lab power supply. It mimics the form, but not the function. For a psychological trick, if it makes you feel like you are in a lab, fine.

But for a lab supply to make any sense, it needs the basic lab supply features, meaning: adjustable voltage, and current limit. These are fundamental.

You can go surprisingly far without these features, for example, by using random wall warts, batteries etc. as explained by rstofer. Series resistors as current limiters. And so on. But then do you need the lab-supply-like neat box? I didn't, I played with wallwarts, batteries, etc. as well, for two decades I guess!

An actually proper lab supply, while useful even for a beginner, tends to be too difficult to build for one. The old magazines and the web is saturated with poor lab supply projects which just cause grieve, and for a beginner it's hard to know which one is bogus. Many beginners get thrown into compensation network analysis in their first project when their DIY lab supply is oscillating, while they could be building an internet-of-things automated coffeemaker out of hot melt glue, cable ties and duct tape.

I did do many LM317-based circuits whenever I needed adjustable voltages, but these were half-an-hour jobs. IMHO, it doens't make sense to spend a lot of time to refining casing and connectors for such a circuit. After all, these regulators ended up going inside the projects in the end. Wallwart, wired to a 7805 in a cardboard box, held together with hot melt glue. Great stuff.

But whatever floats your boat.
techman-001:

--- Quote from: Siwastaja on June 23, 2019, 06:20:46 am ---Getting off-topic, but I don't think building a "lab" power supply out of some 78xx regulators is necessarily a wise project. The reason is simple - it's not a lab power supply. It mimics the form, but not the function. For a psychological trick, if it makes you feel like you are in a lab, fine.

But for a lab supply to make any sense, it needs the basic lab supply features, meaning: adjustable voltage, and current limit. These are fundamental.

You can go surprisingly far without these features, for example, by using random wall warts, batteries etc. as explained by rstofer. Series resistors as current limiters. And so on. But then do you need the lab-supply-like neat box? I didn't, I played with wallwarts, batteries, etc. as well, for two decades I guess!

An actually proper lab supply, while useful even for a beginner, tends to be too difficult to build for one. The old magazines and the web is saturated with poor lab supply projects which just cause grieve, and for a beginner it's hard to know which one is bogus. Many beginners get thrown into compensation network analysis in their first project when their DIY lab supply is oscillating, while they could be building an internet-of-things automated coffeemaker out of hot melt glue, cable ties and duct tape.

I did do many LM317-based circuits whenever I needed adjustable voltages, but these were half-an-hour jobs. IMHO, it doens't make sense to spend a lot of time to refining casing and connectors for such a circuit. After all, these regulators ended up going inside the projects in the end. Wallwart, wired to a 7805 in a cardboard box, held together with hot melt glue. Great stuff.

But whatever floats your boat.

--- End quote ---

Search this page, the only person who has said 'lab' power supply so far is .... you.

I said 'bench' power supply and recommended making a nice one as a first serious project, something to learn new skills in electronics, something to be proud of every time it's used.

Make it so nice and neat that you'd be proud to take it to show a potential employer your skills in enclosure making, layout, wiring and looming and general initiative.

You'd probably get that job over other candidates with their 7805 regulators glued with hot-melt to the inside of a used pizzabox.

Siwastaja:
I don't know about replicating the same ages-old beginner project everyone else has done and proudly shown to their potential employers.  It's like having a kid, you are very proud of it (as you should be!), but everyone else has them as well and yours don't look that special to them.

Well, maybe if you are applying to a really "low-level" job, like in manufacturing? Otherwise, it doesn't show much passion nor expertise IMHO. Just an opinion, I'm entitled to one as well!

I mean, at the time you start moving from a hobby to profession (if that ever happens), the chances are you are already a few steps ahead of that power supply project, and could bring a more recent, more ambitious project that shows off your latest skills better.

The first project I brought with me to a job interview was a microcontroller controlled (before the Arduino era) 10-channel temperature sensor / regulator / heater control (for chemical process control) bare DIY etched PCB hotmelt glued to a plastic plate, and I showed off the UI, menus, temperature measurements... The interviewer wanted to measure his body temperature and it showed some 36.6 degC, success  :-+. Made a better show than a 7805 power supply.

A guy I knew, an avid fresh hobbyist, made amazing progress in little time and I think he brought his IoT smart coffeemaker thingie (which automatically weighed the amount of leftover coffee in the pan, its age, reported it to the social media, and so on) in some job interviews IIRC. I'm 100% positive it's a better show about his skillset (ESP8266, strain gauge amplification, AVR, ADC, internet protocols, product design and prototyping), than being able to neatly route wires to a 7805 and buy expensive-looking connectors from a distributor. This was something he built in less than a year after starting from scratch!

Note, no offense intended. Just wondering your assertiveness on this. Clearly it's an important project for you, and I appreciate that. Building a bench (sorry) power supply is not a bad beginner project. But it's overrated, IMHO, and the functional end result tends to be disappointing. The remaining effect is psychological, and this means it's very much personal with no ground truth. Whether others (such as employers) find the power supply project interesting, is up to a debate. Having done a few interviews, I would prefer the bench supply builder over someone who's done nothing, but would prefer a hotmelt glue IoT coffeemaker crazy scientist over the power supply builder if the job requires innovation and design experience on modern fields. For a production work position involving tying cables, I would pick the one who showed a neat power supply, any day - he/she is probably a very reliable and dependable person.
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