Re: "if your not very much into logic devices.":
On the contrary, I am very much into logic devices - I'd be using such things almost exclusively - for work anyway...
Re: "If you want only power up your iot circuits":
Well... at the end of the day this is going to be the direction I head, but I just started this stuff...
Re: "Ask yourself what voltages and currents you actually need for your IoT development. Try to think of actual situations where you would need more than 12V or 2A.":
I do know quite a bit about the voltage/power requirements needed in this field. I work in software and had a job recently at a IoT company where we were fairly closely integrated with hardware - hanging around the EE lab there inspired all this - and we were working with TINY TINY amounts of power. Our devices were meant to last 5 years and had all sorts of special kit I do not understand to attempt to achieve this. I had to be aware of anything in my code communicating with the device itself, what it would cause the device to do in hardware, and the power cost of it. That's not the point.
Guys, I am just starting to learn low level electronics - in my CompSci degree we started at logic gate level - and practicality is way down the list of priorities. I'm hacking around in a slowly clearing fog. Don't bother asking me what the point is. I literally don't need more than 9V right at this moment but a) I'd like to have it on hand when I do need it, b) I'd like to build it for the hell of it, and c) if I'm going to make an adjustable supply I'm going to need a buck converter at least (to get ~12V down to 1V out) so why not boost while I'm at it?
I don't NEED the old oscilloscope I just bought off Ebay for £50 (after a little tinkering I have a trace on the screen but the probes have no ground clips!!! Arrggg... separate thread) either but I sure as hell want it
Re: "I feel like building a step down supply is a typical project for beginners. What you thus can do is just use an off-the-shelf supply to boost, and then build your own discrete LDO type circuit.":
I did wire one of these up on a breadboard yesterday and it worked first time. Just a couple of resistors (I think forming a voltage divider providing some kind of reference???), a pot, and a couple of caps. Plus the regulator chip itself of course. I don't know if I accidentally built a R-C oscillator! As soon as I get my scope working I'll find out.
The thing is, the bought boost/buck converters inevitably have variable step down built into them. Not using it and hooking up my own linear circuit seems like a waste of power. Especially given the bought converter is supposed to be 98% efficient.
Re: "A good development power supply, will not only supply your circuits, will also measure voltage and current applied, and limit the applied power, avoiding you to burn things due to mistakes":
Good point. I have a little LCD voltmeter ready to slot in the front, but had not considered current much, except in terms of fusing and 'how much can I draw from this particular wire'. How might I provide a constant and/or limited current? This might be a rabbit hole of a question but any recommendations on tutorials etc to read would be much appreciated.
FYI the converter I bought is this:
https://www.amazon.co.uk/gp/product/B0171JFSJ0/Has 3 pots built in - presumably in series and of decreasing capacity to provide fine adjustments. I will probably replace them with a single 10-turn wire wound pot on the front of the device.