| Electronics > Beginners |
| DIY power supply |
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| Pirateguy:
maybe i haven't been clear enough about my motivation. i do not do anything that warrants spending $300 on a psu, or anything else for that matter. my oscilloscope is a first generation dso nano, and i don't own a single component that wasn't the cheapest one i could find on ebay and so far those parts have served me perfectly adequately. such is the simplicity of my projects. i am JUST a beginning hobbyist who wants to upgrade from the complete ghetto psu i have now to a more convenient one. performance is not much of an issue, neither is accuracy. in terms of functionality the collection of wallwarts i have would have served me fine, but i want more convenience. so essentially my question to you is: what is convenient? what can i put in this box, and what manner can i put it in there that will come in handy for a beginning hobbyist like me? what features do i need? what features do i want? what features can i put in there cuz 'i might as well since i have these things lying around and i have the box open anyway'? what would be the more practical way of setting up connectors and switches etc for the above? what 'traps for young players' should i look out for? keeping in mind i will NOT be designing missile guidance systems or medical equipment. i just want a big box that gives me a more convenient way of powering stuff, and it would be nice if it gave me some basic info on what it is doing. THESE are my questions. |
| StillTrying:
--- Quote from: Cliff Matthews on August 03, 2018, 11:54:59 am --- --- Quote from: Pirateguy on August 03, 2018, 08:53:31 am ---i actually ordered 2 function generators. any thoughts on this one? --- End quote --- Yes, it would be nice if someone could comment, to know it's "flakey" :-+ --- End quote --- I've got one, the frequencies are only approx. mine runs about 2% fast. The output TR and 1k pull-up rises ~50ns, falls ~10ns which means narrow pulses % at higher frequencies are off. The + and - buttons and their acceleration work OK, but I'd describe it as set-able rather than adjustable. I've only used it between 5V and 10V, which is enough for it to start getting warm. So it's just about OK for the price. :) |
| rdl:
Too bad you're not in the US. My recommendation for a beginner power supply is one of these: They cover just about all beginner needs and are commonly found on ebay for $100-150 used. I would look for something similar as far as features and specs. |
| HB9EVI:
It's really true: you want to do the 4th step before taking 1,2 and 3. You say it yourself: you are a beginning hobbyist. So why do you want to start all up with an advanced all-in-one device? All you need in a labsupply is adjustable voltage with current limit and a voltage/current meter showing you the actual parameters. So - why not to go - for example - with a LM723? The meters you get on aliexpress or you maybe already have them. You can even do 2 independent channels for opamp circuitry. And: if you want a function generator to buy, watch at least out for a DDS-module with an AD9834. Nobody uses anymore those XR2206, ICL8038 or MAX038; they had their time, but these times are all over. A DDS is also a good diy project to get into uC-programming and the DDS-architecture. |
| Jwillis:
Oh let him have his fun. 40 volts and 5 amps can be a tough nut to crack if using BJTs .Power BJTs safe operating area drops off a lot over 30 volts so even the trusty 2N3055 is only capable of a couple amps flat out at 40 volts .That can shorten the life of the transistor. So if you want them to last you'll have to parallel 4 or 5 to keep the things cool. MOSFETs don't respond well to linear applications but can handle much more amperage when pulsed. Are you going to use MOSFETs or BJTs.Of course this is assuming you would like to build from scratch.Most PSU circuits on the web will only go to 30 volts since most regulators are really only capable of around 35 volts .Even the lm317 has a max rating of 37 volts.There are regulators that go higher like the TL783 if your looking for direct regulation. If I may suggest a floating regulator like the LM723 or similar .They tend to be much more stable and are easier to use.There are others that use op amps as well . There are hundreds of ways to build a PSU .It just depends on how complex and how modern to want it to be. |
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