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 …
Category Archives: My Projects
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 …
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).
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 …
DIY Resistor Decade Box
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 …
Simple Plasma Speaker/HV Power Supply
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 …
Unocharge NiMh battery charger
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 …
NiMH and NiCD battery charger
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 …
