This is a simple network cord tester that uses just 8 unique resistors. The values/wattage doesn’t matter as long as the meter can read them. They should be in the kiloohm range. I have made an Excel spreadsheet file that you can enter all 8 of the resistors and get the total parallel resistance. The …
Tag Archives: diy
Basketball pump signal injector
This is a simple signal injector that can fit inside a mini basketball pump it requires: This signal injector can come in handy for repairing radios, amplifers and old TVs and also square wave generator in a probe. Later on I will make a version that uses C1 and C2 as 470nF and R3 and …
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 …
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 …
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. …
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 …
Capacitance substitution board
In this blog I will show you how to make a dip switches capacitor substitution board. Its very simple since capacitors add up in parallel. So if you look at the schematic you will get an idea.
Simple doorbell/alarm
This is probably the simplest doorbell or alarm circuit that is out there. The buzzer will not be constantly on since the buzzer gets switched on by a capacitor. The circuit draws hardly anything when off as you will see in the graph below. As the capacitor gets charged its current lowers down a lot. …
Arduino Video poker for the TV
Here is a project I have been working on. It hooks up to the tv and allows you to play 5 different types of video poker games. The game is in black and white and some of the suits look funny. The pinouts can be found in README.MD file. Youtube videos
Capacitor powered LED flashlight
Long time ago QVC sold a shakeable Flashlight that had no batteries just a shakeable generator and a super capacitor. This flashlight uses a 5vdc 1.5a wall wart to charge the capacitors. To figure out how long it will take to charge the flashlight you use this equation $$T=5R_{currentlimit}C$$ And for total discharge time $$T=5R_{LED}C$$ …
