This contest is to show your christmas decorations you put up this year. There is no prize but its just to show your christmas sprite. Voting ends 12/31/2023 and posting 12/25/2023. Note you can only vote once
Author Archives: Justin Roeder
Simplest Wire Tracer/Coax Tester
This is a simple wire tester all you need is a 12-1000vac non-contact voltage detector. The ideal is to connect AC live wire to the red circle is. You do not use ground or neutral wires, these wires should be cut off. If the cord is shielded(coax) the detector doesn’t. Even though there’s only one …
Sam And Michael
The easiest RJ45 Cable Tester
This tester is pretty simple and cheap to build. All you need is 2x RJ45 Female connectors(like the ones for putting into the wall) 4x 2-pin Bi-color LEDs 4x 150 ohm resistor USB A Male Connector(I cut a USB Cord) 4x DPST or DPDT Switches A PCB Or floor tile and copper tape Some wire. …
USB Null Power Supply
One time I read an Nuts and volts article where this guy took a usb cord and unhooked the +5v(red wire) and made it where the arduino can be powered by an external power supply without breaking anything.. This can be also handy for power hungry devices(such as external dvd burners,etc). This will draw nothing …
When an soundcard probe uses wrong polarity on android/chromebooks
In this blog I will review the Virtins Soundcard probe using it on a chromebook. Chromebooks use a 4-pin headphone not a 3-pin connector like PCs and regular laptops use. Here comes the interesting part when measuring a sawtooth wave it was going backwords seen on figure 1 What can that do to the circuit? …
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0-30v/0-60v dual power supply
Here’s a type of powersupply you should have. It’s good if you’re dealing with OP amps. I took the circuit from eleccircuit.com and modified it to incorporate 2x printer power supplies instead of an AC transformer. It provides a ground that are both positive and negative. LM317 and LM337 regulators are utilized in this circuit. …
Pythagorean Transistor Circuit
Here’s a circuit that Joerg from the electronics chat shared with me. The circuit outputs a current and inputs a current for the variables in the Pythagorean equation. Pythagorean theorem solves for the hypotenuse of a triangle. The currents in the circuit are the same way where C is the hypotenuse in amps I(A) is …
Fake Flash Drive Tester
This script simply creates files onto the flashdrive to see if it is a real flash drive or fake. All files created by this script should all be the same. It works with all OSes that support PHP. NOTE THIS TOOL IS NOT MADE TO BE USED FROM A WEB SERVER. Batch file is included …
Audio over telephone
Heres a simple circuit that takes a audio signal(from ham radios,computers or cd players) and converts them into a telephone signal. It powers the phone line with 22vdc(It doesn’t have to be 22vdc, different voltage means different resistor is needed). The phones can run as high as 48v. If you use cordless phones the converter …
Circuit Simulator