Bortmoun

I'm intending to use it in low current projects like oscillators, arduino projects - these sort of things - to learn electronic but also I'd love to drive fly-backs for juicier arks (which I've already done with my ATX power supply, of course with the standard measurements and personal protection to avoid electric shock), and olds vacuum tubes. I could instead buy one here. But, for a reasonable price, I could only find Yaxun brand, which I don't take a lot of faith (the good one are like 3 or 4 times the price of these Chinese). I do not think I'll draw too much current from it often... So, this point can be left aside, but, yeah, you're right: by mine calculations, something about 7W per transistor will be lost upon high load. The first question is crucial for my project! Thank you for your reply!

Hi there. I need a good bench power supply, which i want to build myself, for my hobby lab. The thing is, i have been thinking about LM-317 as my linear voltage regulator (and because here where i live i don't have no access to better ones). The design must have these features: a)Current control from few mA to 5A b)Voltage control from 0V to 30V. For this purpose I've built this schematic, which i attached here. Please, tell me what you think about this project or if does work or does not, for i am a beginner in these things. R8 is just a dummy load. The things i need help: 1) How can i add a minimum load (10 mA as by LM-317 datasheet) to keep the power supply operating in different potentials? 2) I need a replacement for 2n3822, i can't find it in my country too. 3) Can I run it from a fixed switched power supply (way more cheaper than buying a transformer here)? 4) In the future, I'm thinking about adding digital control with PWM to this circuit with Arduino or something like that. Do you think this is feasible? Thanks in advance and sorry for my English. PS: i have already looked here in this forum about the 0-30v power supply with op amps, but i really like the LM-317 concept, although i will build this last one if my project fails.