Here’s a simple LED tester that allows you to test LEDs, see how bright they are and let’s you see the forward voltage drop used to figure out the current limiting resistor. We use a 100mA LM317 current regulator. By doing this you can see how the LED reacts to different currents. In this circuit …
Author Archives: Justin Roeder
DIY Holiday Lights
In this blog I will show you how to build holiday lights. This idea came from Penny who wanted to get green lights and come to find out they are not in store.You can take LEDs and wire them in parallel with a current limiting resistor for each one. Or to speed up soldering just …
TV coax oscilloscope probe
In this blog post I will show you how to build a x1 probe and a x10 probe. You will need resistors, a pen(prefer one with the tip can come off),6ft or less of TV coax, paper clip,one alligator clip, 1 Meg impedance oscilloscope and a f jack to BNC adapter. You will want to …
Passive Ethernet Tap
A Ethernet tap allows you to monitor Ethernet communications going through the tap. The circuit uses no power and that is why its called passive. Can be made by cutting Ethernet cords and/or soldering or crimping. This method will make the maximum Ethernet speed 100Mbps, even if its a gigabit Ethernet. Also you could use …
Sawtooth generator for TV oscilloscope
Here’s what I come up with for sawtooth signal for the scope. I took the ramp generator circuit from learningaboutelectronics.com It uses 3/4 Op Amps from the LM324 chip. I tested the circuit from learningaboutcelectronics.com and it works in multisim. S1 and R8 controls the frequency. R6 controls the amplitude of the sawtooth voltage. When …
DIY TV Oscilloscope
Scopes are expensive and hard to find locally. Here we are going to build one out of a CRT TV. THIS METHOD ONLY WORKS WITH CRT TV, NOT PLASMA, FLAT SCREEN OR LCD TV. The circuit only uses the TV Deflection coils to create a magnetic field to attract the electron beam that the gun …
3.8V Li-on battery charger
In this blog post I will show you an easy project that can charge Li-on batteries that have the built-in protection circuit. All you need is a 1A or higher rectifier diode, 1 amp linear adjustable voltage regulator(such as LM317), 240 and 680 ohm resistor(any wattage) and a 100 ohm trimmer(For adjusting the charging voltage).
QInstall An alternative to Windows uninstaller
This tool allows you to uninstall programs as well as see when they were installed. It lets you search through the apps. It can remove files left over by the program. It can clean clean the uninstall registry key. To see how to use it just open the exe file.
WinKill – Program killing tool
This tool allows you to easily end a non-responsive program. Or a whole truckload of them running at once. This tool works by specifying anything that should be contained in window text and/or classname. You can specify the /NR switch to only kill not responding programs. It’s just like Linux’s xkill command.
DIY Music controlled pumpkin
Here’s a simple and easy Halloween project. It is based off of a single ended transistor audio amplifier. The transistor amplifies the audio voltage to one that can light up an LED. The volume should be turned up all the way to get best performance. Since audio singles are hardly any strong. If you want …
Circuit Simulator