Henry T

Imagine you short circuit something! Couple of amps flowing through something isn't fun, no variable current limiting, very "dirty" output, with all kinds of problems resulting...

Best if you are just starting electronics is just to go get a LM317 or something similar a couple of resistors and voila, a variable power supply from 1.2V to ~30V, easy, can deliver an amp or 2, short circuit protected...

Or make a nice little power supply with a couple of opamps and a (big) transistor, with variable current limiting,...

See how I hammer on the fact that you best use a current limiting setup, it saves beginners a lot of frustrations from seeing stuff blow up the moment they apply power...


Just my 2mV though...

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Mikebits

You should try to locate a electronics surplus store in your area. These outlets are a great place to get your hands on a power supply.
Sci.Electronics FAQ: Surplus: USA

Sceadwian

Henry, ATX supplies are short circuit protected. I've never tested the +3.3 volt lines on mine, but tested both the +12 -12 and +5 main lines. I've plugged an RS232 board accidentally inverted into my PC, so it's 24 volts, power supply 'clicks' and humms in shutdown but no damage to any circuits. I wouldn't rely on it for 'serious' current limiting, but for a hobbyist it's wonderful.

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Mikebits

You could always fuse your project as a precaution. Cheap insurance, unless you use a fluke fuse. lol

Sceadwian

LM317 is a linear regulator, so it's power dissipated limited, forget to put a heat sink on it and it goes up in smoke, not so good for a hobbyist that doesn't know it. The ATX power supply takes care of all the nasty details for you for a basic +5 +12 -12 supply.

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mneary

I've used ATX supplies in a professional lab environment. One advantage is the other engineers are less likely to steal them.

Hero999

No it won't, it's thermally protected so it will shut down rather than smoking.

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astronomerroyal

I started from scratch two years ago. I recommend the Tektronix TDS scopes. 2 channel, digital. I have the 1002, bought on ebay for around 550USD. Although I use my DMM more, the scope is absolutely life-changing. Even does fourier transforms.

Dual Power supply: used HP 6205B on ebay for ~100USD.

I've just started with PICs. Bought a cheap 100USD laptop, Pickit 2 programmer and got FREE microcontroller samples from 'sample dot microchip dot com.' It's all free except for the programmer. Bye.

Mikebits

Wow $550 for a Tek digital is a good price. I am still just using a Tek 2236 analog which I picked up at a swap meet for $200.

hugoender

Why did you have to buy a $100 laptop to program a PIC? Also, is PICkit2 better than Junebug? From what I have read Junebug has everything PICkit2 has and some.

Speaking of equipment for hobbyists... I am looking to purchase a very basic/cheap laser printer to create my own pcb's. Anyone know of any good laser printers that are cheap?

hugoender

Is a Tektronix TDS-220 Digital Oscilloscope a good buy at $600?

Mikebits

Why use your main and expensive PC to program PIC's? Better to lose a $100. laptop than your business end of computing.

Mikebits

I would say yes if it works and is in good shape. Any extras like probes?

hugoender

Why would you lose your computer? Is it possible to damage your computer when programming PICs!? If so, do the programming kits such as Junebug and PICkit2 come with some sort of "fuse" to prevent damage to your computer? If not, then I guess I will have to whip out my 9 year old Gateway desktop computer that has been accumulating dust in the corner of my room

Mikebits

I guess my point was, it is nicer to use an expendable PC for projects than your main use computer. I am sure the odds of frying a PC are slim, rather than just an interface card, but why chance it if not needed?