| Electronics > Beginners |
| DIY power supply |
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| MarkF:
--- Quote from: Pirateguy on August 13, 2018, 01:11:58 am ---on the topic of function generators, i do have some ICL 8038 ICs that i could build one with. i also have various arduinos and one of those cheap arduino starter kit LCD displays, as well as a small tft screen. how would u rate the challenge level of such a project? incidentally i have put together that XR2206 thing and BOY does it suck! lol i might try to implement those improvements in those videos posted, but i'm not sure it's worth it. prolly end up using it in some project for some specific task or something... --- End quote --- It looks like the ICL8038 works in a similar fashion to the XR2206. I would predict a similar result. But, it maybe a worth while exercise to gain experience since you already have the chips and they only need a few external parts and NO microprocessor required. If you want to build a function gen, I still feel a modern DDS like the AD9834 will give you better results. However, they are $12.00 each and have a SPI interface. Since you already have an Arduino and some small displays, you could start by just programming the display and controls with no initial monetary investment. Here is the display I did for my function generator to give you a starting point (There is a PIC hidden under the display): You are definitely going to need a scope to do some debugging. |
| Pirateguy:
i'm not sure what is more practical, but for limited room for jacks n stuff i think i am gonna go with the rotary switch. my ATX has lots of red, black and yellow, but only 1 white, blue and orange wire. there is a thick shielded bundle of wire connected to the board and power jacks that has a big switch on the other end to be mounted in the PC case. maybe the sense wire is in there? i also read something about having a load resistor on one of the outputs for some reason. thinking about pulling one off this $1 usb dummy load thing i have. if i ever put in a high voltage output i intend to have a separate transformer, inside it's own compartment in the housing, fully isolated from all other stuff. maybe something like a halogen ballast or a neon sign transformer or something like that. though more likely it will just a ZVS driver, keeping the actual high voltage stuff external. my ATX is just a 200 watt one. --- on the topic of fin gens: from what i understand the xr2206 is not that terrible up to 12v, and it is mainly design flaws in the board that make this module crappy, aside from already being cheap. hopefully i wouldn't make those mistakes and maybe i could use multiple chips for better performance. like dedicate a chip to each waveform, or have different chips for frequency ranges or something like that... unfortunately i don't have a proper scope. i do have a OSD nano (first gen) but i think maybe i should hold off on this till i get a proper bench one. |
| MarkF:
I think you have that backwards - * Power Supply I can think of lots of projects that would require multiple voltages. Essentially, any analog project that includes a microcontroller. A function generator for example could require +5V, +12V and -12V. I currently have six power supplies on my bench. Old ATX Power Supplies required a load on the 5V rail to start. An adapter I bought (never used) included a 10 ohm 10 watt resistor. The adapter also included fuses. An ATX power supply DOES NOT have any current limiting and can ruin your day. http://dangerousprototypes.com/docs/ATX_Breakout_Board IMHO: An ATX power supply is not a replacement for a proper lab supply. * Function Generator In almost every case you will only use one signal at a time. The only case I can think of would be if you needed some kind of modulation. |
| Pirateguy:
well i have some 0.9A poly switches, but i also have some breakout boards with step down converters for arduino. they have 3.3 and 5v. also the rotary switch i have has 12 positions :D |
| MarkF:
I do like these little HP Supplies. Not a lot of power but without a fan, they are quiet and don't take up much space. HP 6216A Power Supply Also, an AD9834 DDS Signal Generator Sine/Triangle/Square Wave Generator module that you could interface your Arduino to. AD9834 Module |
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