In this blog I will show you two ways to make a cable tester. The 1st way uses a arduino (software controlled). The 2nd way uses a decade counter chip(CD4017) and a flashing LED. I am going to order the Dual RJ45 jack to screw terminals from eBay. The other connectors are from parts-express. I …
Category Archives: My Projects
6AL5 low voltage logic circuit
In this blog we will experiment with vacuum tube logic gates. We will be using low voltage so it is totally safe. We will use a 6al5 twin diode tube. In the circuit below shows how to use it as semiconductors diodes but it’s very same as for vacuum tubes. Simply wire positive and negative …
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
Serial Port PWM
In this blog I will show you how to generate pwm with a computer with a serial port. This tool was originally written by subcooledheatpump from YouTube. I made it better where you can choose which com port to use(by command-line or by being prompted to do so). Controlling it is now better since now …
The simplest in-circuit transistor tester
This is the simplest in circuit transistor tester. It uses two ammeters to measure the transistor gain. It is kinda like the heathkit IT-18 one but uses 2 meters instead of one. I plan on using relays for the polarity switch instead of a 5PDT Rotary switch. It uses a LM317 regulator for providing a …
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Discrete transistor op amp
Here in this blog i will show you how to build a high powered transistor opamp. The design is based off of allaboutcircuits.com design. The only changes were the transistors were power transistors and rprg is lowered to 390 ohms half watt.
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 $$T=5R_{LED}C$$ …
Yet another TV oscilloscope
In this blog post a crt TV a part and turn it into a oscilloscope. I am going to try to use a TL082 op amp to buffer and amplify the signal. It uses the deflection yoke to draw the picture on the tube. More pictures and videos will be posted here when it is …
Circuit Simulator