This tiny shell script will allow you to backup the settings and programs from a live linux session to two .tar files. Here’s a list of the tar files and what they do. config/data.tar – Configuration and settings files. (/var and /usr directories) if any of the files in data.tar exists it will be overwritten. …
I had a 6vdc power supply laying around and John Zogg(my friend) wanted to power his scanner from both batteries and power supply. The power supply didn’t have the correct connector. So what could I possibly do to safely run it off of the batteries and power supply at the same time? So I got …
This is a simple yet effective resistor decade box. The resistors are connected in parallel with the SPDT/SPST switches. The resistance is the sum of all switches opened(NOT CLOSED!). When resistors are in series the resistances add up. $$Rt=R1+R2+R3$$ And when they are in parallel the total resistance decreases: $$Rt=\frac{1}{\frac{1}{R1}+\frac{1}{R2}+\frac{1}{R3}}$$ Rt is the total resistance …
I wanted a solution for making my visitors easier for them to order parts to build my projects. This code comes from the “Order By Part#” Page. Heres an example of how to use it: Heres the source code of the utility: Real Example
This circuit takes 3.7vdc and converts it to about 18kv. The transistor is used for the plasma speaker. It’s basically a Single-Ended Class A Audio Amplifier. The 500-ohm pot adjusts the voltage sent to the converter. The pot must NOT go over 500 ohms because then the voltage could be too high. The circuit is …
When I got John zogg’s DVD player it didn’t come with the AC adapter, just the carrying case, battery and the car Cord. At first I thought that it would of charged on 12vdc, but no it has to be 9vdc. So what I did is buy a adjustable voltage regulator, heatsink and a couple …
Here is my plan for John Zogg’s battery charger. It uses 3 analog inputs for each battery cell. I decided to use this one that flyback found on the internet is because it can turn off when it is done. It has a temperature sensor. It uses an Arduino Uno to control it. USB is …
Here is a simple transistor battery charger it can charge batteries up to 12v in series. It has an LED and a few parts. To use it you must decide on a power supply voltage, current limit resistor, and number of cells. First to figure out what voltage to use you must know the total …
Today I began working on my Capacitor box. It’s value is in binary obtain from switches. If you can’t get perfect Capacitance from each switch you can use multiple in parallel or series. For capacitors in series the value is: $$Ct=\frac{1}{\frac{1}{C1}+\frac{1}{C2}}$$ Both equations can have any amount of capacitors the variable Ct is the total …
This do-it-yourself extension cord is simple and straight forward. The reason! Why I built it was to make my cell phone reach the outlet. I just used 2 strains of wires connected to both ends. The one I built has 3 different kinds of wires. This is because I wanted to build it out of …
Circuit Simulator