ATX benchtop conversion retains safety features, delivers plenty of current.


[Bogin] was looking to add a benchtop power supply to his array of tools, but he didn’t really find any of the online tutorials helpful. Most of what he discovered were simple re-wiring jobs utilizing LM317 regulators and shorted PS-ON pins used to keep the PSUs happily chugging along as if nothing had been changed. No, what [Bogin] wanted was a serious power supply with short circuit protection and loads of current.

He started the conversion by disassembling a 300 watt ATX power supply that uses a halfbridge design. After identifying the controller chip, a TL494 in this case, he proceeded to tweak the PWM feedback circuit which controls the supply’s output. A few snips here, a few passes with a soldering iron there, and [Bogin] was ready to test out his creation.

He says that it works very well, even under heavy load. His tutorial is specific to these sorts of PSUs, so we would be more than happy to feature similar work done with those that implement other design topologies. In the meantime, be sure to check out a video of the hacked power supply in action below.

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Variable capacitance/reistance switch box has you covered


While working on electronics projects, it’s often necessary to test out different capacitance or resistance values as things are moving along. Depending on what you are testing, this can be a tedious process even when using a breadboard. Instructables user [mattthegamer463] recently built a very useful device that would help out in these situations, and would likely be a welcome addition to any Hackaday reader’s workbench.

His variable resistor/capacitor box makes it easy to test out any number of different resistance or capacitance values with a simple turn of a knob. He wired up a pair of pots to provide a wide range of resistance values, being sure to add a low-resistance safety as well as safety override switch for those of you who like to have things blow up in your face live dangerously. A set of 22 capacitors were wired up on a piece of perfboard, each of which can be selected using a pair of knobs. He added a simple switch to allow the capacitors to be toggled between parallel and series orientations as well.

[Matt] did a wonderful job here – this is a great project that can be customized in a multitude of ways to fit almost anyone’s specific needs.

PC casemod-inspired benchtop PSU


[Will] had a cheap power supply sitting around, and decided to turn it into a full-featured benchtop PSU. Inspired by some of the other benchtop supplies we have featured in the past, he decided that he wanted his PSU to be more than just a simple-looking box sitting on his work bench. Taking some cues from PC case modding, he put together a unit that is not only very useful, but also quite sharp looking.

The frame of the case was crafted from aluminum angle, while all of the other flat surfaces were made using black polycarbonate. He installed the standard 12v, 3.3v, and 5v terminals you would expect from any benchtop PSU, complete with an LCD display showing the voltages provided by each rail as measured by an Arduino stationed inside the case. Additionally, he installed a variable terminal capable of providing 1.3v-30v, along with its own LCD display. The most unique feature is the multimeter embedded in the front of the case, which makes it virtually impossible to lose.

The case is finished off as you might expect, if you have seen any of his previous work. It features LED lighting on the inside, large fans on either side of the case for optimal air flow, and a pair of machined aluminum handles.

Be sure to check out the quick video below of the PSU being powered on.

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