# DC Power Supply & Soldering Iron Recommendations?

Thread Starter

#### icydash

Joined Jan 14, 2009
124
Hey guys!

I'm looking to buy a (at least) dual-output DC power supply to use with prototyping my home projects. Just something similar to what you'd use in college engineering lab, nothing fancy. Does anyone have any recommendations? Obviously the cheaper the better, but I'd like to not spend more than $400 on this. I'm also looking for a new soldering iron set up, preferably digital, and not more than$200. Recommendations for this would also be greatly appreciated.

Finally, I'm also looking for a new -surface mount- soldering iron set up. Again, recommendations would be appreciated. I'd like to not spend more than 2-300$on this as well. Thanks!! I apologize if this is in the wrong thread area, I wasn't sure where to put it. #### ajm113 Joined Feb 19, 2011 174 Well I did buy my power supply for a good price, but it's not that flexible. Honestly if I was you and wanted more flexibility out of your power supply and have it "cheap" as possible, build one! They aren't that hard to make and it's a good way to introduce yourself using AC current and turning it into DC. You can honestly get everything you need at Radioshack(If you want these locally and quick ) Other really good options are Jameco.com and element14.com. (If you want to save some money and get realistic prices) Project Box, Transformer, Diodes, LED (Power On), Power Switch(es), Multipurpose Nylon Binding Posts, 47000μF Capacitor, Fuse/Polyswitch, volts meter, variable control resister and a knob to go with it. Wires of course and honestly you can get a AC wire for the outlet from any old electronics, that uses a outlet from anywhere for free. This is a really good tutorial to help you get started: http://www.youtube.com/watch?v=GMePE7NZcxw Anyways if you prefer buying a power supply with everything, go on ebay or do a google search on dual power supplies on the Shopping Tab. As for the soldering tools, I'm not sure about a digital soldering iron. It's kinda a over kill on a feature if you ask me. =/ I prefer the old fashion ones. That have a high, low and off setting. Hope this helped! -Andrew Thread Starter #### icydash Joined Jan 14, 2009 124 Hey guys! Thanks for all the insight. I'm definitely looking to buy, rather than build, the power supply. I know they aren't that difficult, but I'm in law school and have little time, so I'd rather buy something ready to go then have to do a project to get to my project I was thinking possibly this: http://www.mastechpowersupplies.com/mastech-regulated-dc-power-supply-hy5005d-2.html --> It's on sale for$250.00. I know it's more than I need (50v and 5A), but it seems like an OK deal.

The video on the essentials of an electronics lab was great, but unfortunately he recommended only build-it-yourself power supplies whereas every other tool he recommended one could buy. It was very helpful for soldering irons, though.

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#### BillB3857

Joined Feb 28, 2009
2,546
Check www.mpja.com for all kinds of items. Single and multiple power supplies, soldering tools, component, etc.

#### someonesdad

Joined Jul 7, 2009
1,583
One of the cheapest ways to make yourself a nice power supply is to get some good switching wall warts from a second-hand store. Now, you can't really test a wall wart to find the good ones unless you have a scope and a DC load (or make an equivalent). However, I've found that the HP wall warts for their laptops are quite good and the unit I have puts out 12 V at 2.5 A. It's usable beyond that in fact. Put two of those in a box with some LM317's on heat sinks and some pots to adjust the voltage and you'd have a very nice setup for very little money and time.

However, I prefer to buy good lab-quality power supplies. My favorite power supply is my HP E3615A, which outputs 20 V and 3 A. It's constant voltage and constant current and uses 10 turn pots to adjust voltage and current. It gets used a lot. However, it's only a single supply. You can learn a bit more about this series of power supplies on a EEVblog #166. I got mine for $100 on ebay about 6 or 7 years ago and it looked like it was brand new. Agilent still sells these models and they are quite good linear supplies. Actually, if I could have only one power supply, it would probably be the B&K Precision 9130. It's expensive ($895) -- but it's a triple output supply that's a bit of a sleeper. Personally, I wouldn't have spent that much money, but I got mine in a trade for substantially less and didn't have to hork up any cash. It has two identical 30 V @ 3 A supplies and a 6 V @ 3 A supply. Typical use is to set the two 90 W supplies to track each other to get your + and - bipolar supplies and use the other supply for digital power. Or, you can connect them all in parallel to e.g. get 9 A at 5 V. Connect them all in series to get up to 68 volts at 3.1 A output. I've found with my system voltmeter that it outputs the voltage you type into it within a few mV of what you asked for (although the display might indicate a bit farther away). It's also fully programmable over a TTL serial port. It has a programmable overvoltage limit for each supply -- for example, you can set the supply to 12 V output maximum so that you can't fry a particular circuit no matter what values you type in or how you turn the knob. You can choose whether to have it resume its output state after a power cycle (which supplies are on and their settings or either of those). There's 50 different registers for storing particular setups. My only complaint about it is the firmware for knob adjustments is a bit sluggish. But I usually just type in the voltages and currents I want, so it's not that big of a deal (I use my HP supply when I want fine knob control).

Thread Starter

#### icydash

Joined Jan 14, 2009
124
Thanks guys.

Does anyone have any insight into a surface mount iron or anything? I remember doing some surface mount soldering a year or two back in my lab, but I can't remember what tools they had. There was some kind of pump/syringe or something to push out the solder paste and then a special iron to heat it up. I can't remember for the life of me what the solder paste is called/brand/contents and what kind of syringe/soldering iron it was.

What solder paste/set up is good for this?

#### ErnieM

Joined Apr 24, 2011
8,177
A pre-built lab supply is always a good investment. My preference is a single 6V adjustable or 5V fixed, plus dual adjustable outputs. That said you have an excellent supply picked out.

I have a hot air reflow plus conventional iron like the link. I mostly use it for hot air with is is excellent for. I already had a fine point iron for "touch" reflow. Careful if you get the "hot air only" version, they are only 220V

Thread Starter

#### icydash

Joined Jan 14, 2009
124
A pre-built lab supply is always a good investment. My preference is a single 6V adjustable or 5V fixed, plus dual adjustable outputs. That said you have an excellent supply picked out.

I have a hot air reflow plus conventional iron like the link. I mostly use it for hot air with is is excellent for. I already had a fine point iron for "touch" reflow. Careful if you get the "hot air only" version, they are only 220V
What is the hot air gun for? I've never seen that before.

#### ErnieM

Joined Apr 24, 2011
8,177
What is the hot air gun for? I've never seen that before.
Its for manual reflow of teeny tiny surface mount parts. You squirt out little dabs of solder from a syringe (commonly available), drop the part on them and then using just the hot air you get the solder to reflow.

As the parts get smaller you need to cut down the rate of air flow as you can blow your teeny tiny parts into the dark corners of your bench.

Works to unsolder stuff too.

Thread Starter

#### icydash

Joined Jan 14, 2009
124
Its for manual reflow of teeny tiny surface mount parts. You squirt out little dabs of solder from a syringe (commonly available), drop the part on them and then using just the hot air you get the solder to reflow.

As the parts get smaller you need to cut down the rate of air flow as you can blow your teeny tiny parts into the dark corners of your bench.

Works to unsolder stuff too.
Sorry, I don't know the lingo really haha: By "reflow" you mean like... melt and then harden the solder, creating a normal solder joint?

If so, that sounds much easier than trying to solder each side of the surface mount crap with an iron.

Also, how do you like the soldering iron on that two-in-one air blower/iron thing? Is it good? I may buy the one from the eBay link you sent me.

#### ErnieM

Joined Apr 24, 2011
8,177
Sorry, I don't know the lingo really haha: By "reflow" you mean like... melt and then harden the solder, creating a normal solder joint?

If so, that sounds much easier than trying to solder each side of the surface mount crap with an iron.

Also, how do you like the soldering iron on that two-in-one air blower/iron thing? Is it good? I may buy the one from the eBay link you sent me.
WHY it is called "reflow" is beyond me, but yes, I mean melting the solder to your part the first time to make a normal joint. The solder syringe comes loaded with really teeny tiny solder balls (you need a microscope to make em out) in a flux slurry.

Even 0402 resistors, SOTs, SOICs, all are no problem.

It is much easier then using an iron for just about anything except a 100 plus pin quad flat pack I did a few times. Those leads are so close & tiny you need to use an iron to fix the corners, and then do each pad individually, least you get a ton of shorts.

As far as the iron side goes, since I already have a wonderful Metcal iron iron I just unscrewed that side of this thing. I have an associate who used it ans said it was good (but my Metcal is great).

Thread Starter

#### icydash

Joined Jan 14, 2009
124
WHY it is called "reflow" is beyond me, but yes, I mean melting the solder to your part the first time to make a normal joint. The solder syringe comes loaded with really teeny tiny solder balls (you need a microscope to make em out) in a flux slurry.

Even 0402 resistors, SOTs, SOICs, all are no problem.

It is much easier then using an iron for just about anything except a 100 plus pin quad flat pack I did a few times. Those leads are so close & tiny you need to use an iron to fix the corners, and then do each pad individually, least you get a ton of shorts.

As far as the iron side goes, since I already have a wonderful Metcal iron iron I just unscrewed that side of this thing. I have an associate who used it ans said it was good (but my Metcal is great).
Generally I'm weary of companies I've never heard of (Sky Enterprise USA?). I also can't seem to find this iron on their website anywhere, or any customer ratings on it anywhere. But if you say it's good I'll give it a shot.

I've been trying to find a manual for it but can't seem to find one anywhere.

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#### ErnieM

Joined Apr 24, 2011
8,177
Sorry I don't see Sky Enterprise USA. The hot air station is an EBay thing from some unknown Chinese manufacturer. I see lots of EBay companies from china selling these and if it looks like a Canadian or US company it's likely just a local warehouse for a Chinese distributor.

However it is very inexpensive, like 1/5 to 1/10 price of other units to do the same thing, and the dang thing actually works.

Thread Starter

#### icydash

Joined Jan 14, 2009
124
Sorry I don't see Sky Enterprise USA. The hot air station is an EBay thing from some unknown Chinese manufacturer. I see lots of EBay companies from china selling these and if it looks like a Canadian or US company it's likely just a local warehouse for a Chinese distributor.

However it is very inexpensive, like 1/5 to 1/10 price of other units to do the same thing, and the dang thing actually works.
Ok I'll give it a shot.

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