Build Your Own Import Variable Lab Bench Power Supply

Does it ever just kill you that someone in a factory somewhere got to have all the fun of assembling your bench tools? There are a lot of questionable circuit boards floating around the Internet, and they can replicate practically any section of a circuit. When it comes to putting a prototype these days you can pretty much just buy each block of your system’s overview flowchart and string them together. [GreattScott!] combines a few of these into a relatively useful variable power supply with current limiting.

Admittedly, this is more of academic exercise if your only metric for success is monetary savings. Comparable power supplies can be purchased for the same amount of local currency as the parts in this build. However, there is something to be said for making it yourself.

The core of this build is based around the LTC3780, a bit of silicon from LT that offers both buck and boost converting along with a current control mode. It’s useful for a lot of things. The here is rated for up to 130 watts of power, which makes is a decent amount of power for a bench supply.

With a few modifications, like replacing the world’s most untrustworthy potentiometers and adding a nice ABS box, the build is completed. Along the way, [GreatScott!] offers a few tricks for testing and some reminders of how not to make yourself dead when playing with electricity.

The end is a working lab bench supply project that can easily keep a hacker entertained on a lazy Sunday afternoon.

Continue reading “Build Your Own Import Variable Lab Bench Power Supply”

Variable capacitance/reistance switch box has you covered

variable_cap_resistor_box

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.

Two input devices made with common items

Here’s two input devices you can easily build with materials you already have on hand.

To the left, [John] built a 3×3 keypad matrix from paper and tinfoil. The rows and columns are made up of strips of tin foil on the front and back layers of paper. The layers are separated by spongy double-stick tape. A ‘keypress’ results when the gap between the conductors is compressed with your finger.

In much the same way, [Dave Fletcher] built a touch potentiometer. He made two resistance plates by scribbling pencil lead on sheets of paper. When the two plates face each other, separated by the same type of foam tape as before, they can be pressed together to form a circuit with a variable resistance. This results in a crude version of the SparkFun softpot.