Elenco AC/DC Triple Output Power Supply Kit

Okay, there are a number of reviews here on Amazon that point out the cons of this unit. Allow me to say this about how the regulators are installed on the heatsink. The only way to keep costs down as well as build assembly simple, is to use this method. Other options would require active cooling with a noisy fan and internal heatsinks with pin guides for the PCB which for people new to kits like this (and Elenco designs this series for students), would increase difficulty. If you've never loosely stuck a TO pack to a pin guided heatsink (with thermal grease), then tried to tighten things up and solder in place, then finish screwing it in place before ( and that would have to be done four times in this kit), then this is a much simpler solution. All things considered I would prefer to have the individual heatsinks on the PCB, but I do get the design for cost and build simplicity. But as others have said make sure you heat shrink the exposed leads of each of the TO packs, so make sure to have some on hand. Now for the binding posts, there is no excuse. Elenco not only picked the cheapest posts they could find, when it became a problem they didn't bother to correctly address the problem. See a modern, quality binding post will be hard nickel plated on the post part but the area you attach the wiring will either be gold plated or bare, polished copper. Why? Because you can solder to gold or copper. You cant really solder to nickel very well. The reason they are fully nickel plated is because of costs. Nickel is a good electrical conductor (not great, but good enough), and really resists wear from the constant friction of plugging and unplugging of your leads. So thats a good thing. But when these cheap posts are made, they just plate the entire steel part in nickel instead of just the binding part and then polishing the internal hookup part as that is several extra steps that raise costs. So Elenco decided that on the 2010 revision of this kit to include 7 extra nuts but not add instruct the builder that they should just use the extra nuts to attach the wires in place with. Now the overall quality of the posts is fine, you just cant really solder the wires to them easily. Trying to use the extra nuts to bind them to the posts in cramped quarters is also pretty annoying. Run down to your local Radio Shack and pick up a $2.00 pack of 22 gauge ring terminals (catalog 64-3114) and use them instead. Just give yourself and extra half inch of wire on each of the binding post wires. Strip off one full inch instead of the 1/4" the instructions say. Double it over and solder it together. Then crimp it in the ring terminal and screw into place with the extra nut. Much simpler than trying to solder the posts or holding the wire in place in such cramped quarters. Other than that, the only parts I found that were just bad were a couple of caps. One of the 22,000µf and my 47,000µf were right at the very brink of their +/- 20% range, so I upgraded all my caps to new, high temp, low ESR caps that should last a good decade or two. Total price was an extra $7.00 with shipping. So if you can, check your caps before you build. You should be fine, but caps are cheap and good ones will last for a long time. A few do's and don'ts for the kit: Dont use the included lead free solder unless you have a tip and iron for lead free solder. Its hard to work with, it eats up your tip, and requires a good bit of excess heat. Do get some .20, .30, or .40 size 60/40 or 63/37 lead solder with a rosin core. When it comes to electronics, lead is indeed your friend. Don't use the included two pieces of plastic based heatshrink tubbing. Do get an assortment pack of different size heatshrink tubbing and use that instead. Heatshink all exposed contact points in the kit with individual tubes and not just one big one. This kit can be modded a bit. Like many who have built this kit, I chose to install a couple of 2k, 10 turn, wire wound pots to make fine tuning type adjustments. The simple carbon pots that come with the kit will work just fine. I just wanted more precision (ie fine tuning) when setting my voltages. If you don't happen to have a couple of these in your parts bin, then they will cost a bit. Upwards of $35.00 for two with shipping. That includes an extra few bucks for new dials since the included dials, wont fit most multi-turn pots. If you go this route, you will have to drill out the holes just ever so slightly more. We're talking just a hair or two. There is also plenty of room for a display to be installed in the company logo area of the front panel. I will be adding one in the future as I can see that checking my voltage every time with a multimeter will become a bit of a pain. I've already seen one kit where somebody installed a 20 x 4 line LCD display for this and it reads voltage and amps for all outputs. There is even a little extra room between the AC and DC rails for installing a load circuit, which I plan to do. So you can spend twice the price to upgrade this kit if your not careful. Keep in mind that most of these mods are just fun to add and helpful but are not needed. For that amount of cash you could just but a PSU with a display, and fine tuning built in. But the main reason to do it with this kit is it offers dual adjustable DC jacks at 1 amp, a constant 5v DC at 3 amps, and a 6.3/12.6v AC. You cant come anywhere near a quality tri-rail PSU at the $120-$130 mark. So the mods can be fun, useful, let you learn a little if your new to electronics and offer serious bang for the buck features that you would normally pay several hundred bucks for in a prebuilt PSU. The case and transformer are very well made and should last a very long time if treated with care. The taps on the transformer are made with silicone covered wire (which really surprised me) so they wont get brittle with age and heat like the common PVC types. The overall circuit is very simple, through hole based so if a componet happens to fail it would be an easy fix. All in all, its a great value kit that offers lots of upgrades options and should last a long time. I got it in January when Amazon was selling it for $49.00 (with prime), and I see that its now up to $59.00. That seems to be the average price online, so I dont think it will really go up more than this. I've put about $40.00 in parts and upgrades to it, and I'm very pleased with the end result. When I'm finished with future upgrades it will be about $120-$130 spent and I'll have a very versatile PSU, thats cool running, silent, and built to last. I give it five stars. ***EDIT*** Quick tip for building: Flux and tin ALL the PCB solder pads before you begin to populate the board. The solder pads on the PCB are beyond huge and if you try to solder components without the tinning, it will make the work much slower as it will take forever to heat up those large areas and leave your iron on your parts for to long. Don't forget to clean off any excess flux when you are done assembling the PCB.

It's a good project and I enjoyed making my kit. There are several excellent reviews of this item here such that all I can really do is reinforce a few points: This is not a kit for a total novice. Be especially careful on page 9 of the instructions. If you're going to mess up, you really don't want to do so on the high-voltage side of the transformer. If you have some heat-shrink tubing, you should use that on each AC connection individually, and throw away the provided, oversized stuff. I recommend using 60-40 tin-lead solder and a separate, liquid flux instead of the provided, rosin-core leadless solder. Otherwise, you may be in for a few cold solder joints. As others have stated, the pads on the circuit board are oversized and hard to heat up; it's also kinda tough to solder to the binding posts. The binding posts I received have doubled nuts on them so you could use crimp-on ring terminals instead, but I don't recommend that...they would work loose over time. When you're breadboarding something you want a power supply you can count on, not one that has an intermittent problem of its own. Soldering to the leads of the ICs and power transistor is definitely a little fussy. Slip some heat-shrink tubing on the center lead and that will help you avoid them shorting out when you screw the heat sink to the case. As others have stated the reason Elenco did it this way is difficult to fathom. It's no more economical and I would much rather solder in a few jumpers on the board than run fragile, 22-gauge wires to these components. Some of the components are kinda cheap, especially the pots and caps. They should have provided another piece of mica for the LM7805. I powered up my unit for the first time today and here are the readings: AC 6.88v left, 6.87v right, 13.76v across the hots. A little higher than the labeled 6.3v, but these are tapped directly from the transformer so depend only on the transformer wiring and mains supply. DC regulated: 5.02v DC negative: -1.289 to -16.87v DC positive: 1.276 to 20.17v ( This can happen when you use cheap pots. ) I did not bother to short-circuit test the LM317 and LM337. They will either do their job or they won't, and sooner of later that test will occur by accident. Bottom line is that I had fun making it and now have a serviceable supply for about what I would have had to pay just for the case, binding posts and heat sink.

I purchased this kit about a month ago as I had a need for a multi output power supply that was easy on the budget. Everything in this kit was well designed and laid out, case was pre-drilled and labelled, instructions were written in an easy, step by step process. For those who are developing an interest in electronics, this is not only a good starting kit, but also a great starting point to supply power to subsequent kits without needing to use "wall wart" power adaptors. This will be a great asset to my electronics workbench and it will be for yours as well!

This kit is great! I have purchased kits from Elenco before and I have not been let down yet. When the package arrived at my home, I was slightly surprised at the weight (its fairly heavy for the size). I immediately opened everything and began to assemble the kit. The instructions were clear, and easy to follow. And everything needed was included in the kit. No parts were missing. The only problem I had was that a couple of the screws used to hold the components were difficult to use due to the lack of space in the case. After some failed attempts I got the screws in though. Although the size makes putting it together difficult, it also means that the power supply takes up less space on your workbench/desk. Once everything is together, there is a section in the book for testing it, including load testing, and also a troubleshooting guide. Once together, this product worked exactly as I expected it to. I use it with a breadboard to do some basic prototyping. This power source is a great replacement for batteries for test projects. Some tools required for this project are: soldering iron, soldering tip cleaner, pliers, wire cutters, wire strippers, phillips screwdriver, a multi-meter (for testing) and some basic electronic knowledge.

Very fast shipping - received the kit in a couple days (without Prime); one of the transformer legs arrived bent - seems a common issue based on the YouTube videos I’ve seen (it bends back into position easily). Assembled the kit slowly over a weekend - no problems; the manual is very detailed and easy to follow. The unit works perfectly, the +1.25 - 15 VDC outputs produce slightly more than 17.5 VDC (35 VDC combined); the fixed 5 VDC output is very accurate (measures 4.98 VDC). I’ve incorporated a cheap Watt Meter on the output leads to display voltage, current, etc. Overall I’m happy with this purchase - it’s clearly not a professional bench power supply (hence being sold in Amazon’s Toys & Games department; but should be fine for hobby work, charging the odd battery, powering light electronics, etc.

A well designed, basic linear power supply. Every experimenter's bench should have one. I paid CDN $70 + HST, with free shipping (Jan. 2014). Price seems to vary. Good value. My only major criticism is regarding the cheap quality of the binding posts. It's very easy to cross-thread the mounting threads. Tip: use the inside-teeth lock-washers that are provided (in an easy to miss little plastic bag), not the split ring lock-washers that come already on the binding posts. Also, the holes that are drilled in the binding posts for wires were randomly oriented; they may end up horizontal or vertical or somewhere in-between. I had to disassemble them and re-orient the holes so that they ended up being vertical. I used the supplied solder (there was barely enough) which was labelled as tin-copper alloy (?) with a 700 degree soldering iron tip. No problems were encountered soldering, although most of the circuit board holes should be reduced in size. Otherwise, it went together quite smoothly and performed perfectly right from the start. Ken, Toronto.

Wasn't expecting a kit but it is what it is. I like the fact it technically has 6 separate outputs 6.3 VAC, 6.3 VAC (12.6 VAC total), +5 VDC, +1.25-15 VDC, -1.25-15 VDC. the AC common is shared between the two AC outputs and the DC common is shared between all DC outputs which is acceptable. The negative side is assembly is painful. The wiring from the board to the heat-sink components was frustrating to say the least. I would recommend cutting the wires a little longer in order to ease the soldering. I ended up cutting out the casework above the heatsink and wiring the board and IC's as a unit then doing the transformer supplies and and then mounting the board to the chassis and finally the terminal posts and pots. The terminal post soldering was a bit finicky and I didn't realise I could of used the hex nuts until halfway through. I would class this as an intermediate build due to the cramped workspace and awkward layout of the PCB. I will install a volt/ammeter into the front panel for easy reference. DROK®0.28''LED DC0-100V 10A Digital voltmeter Ammeter 2in1 Multimeter 12V/24V Voltage Amperage Meter Volt Amp Gauge Panel with Red/Blue Dual Color Display and Build-in Shunt for Car Auto Boat Battery Monitoring