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 5v through 6.3v ac or dc to the heaters. Use plate pins as the anode.
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.
You may be thinking that usb charging devices use just the 5v and ground wires? Well your wrong as those devices don’t want to break the charger by drawing too much current. They require certain voltages on the 2 data lines. It took me alot of research to figure out how to configure it. If you want you can try shorting the green(data+) and white(data-). This may charge at the wrong current or refuse to charge.
Here’s 3 different voltage dividers simulated in everycircuit
Those are configuration values used in chargers. Here’s a list of voltages.
| Data+ | Data- | Information |
| 2v | 2v | 500mA |
| 2v | 2.7v | 1000mA |
| 2.7v | 2v | 2100mA |
| 2.7v | 2.7v | 2400mA |
| 1.2v | 1.2v | Unknown Samsung devices |
I used r1 as 60k (51k+9.1k) and r2 is 75k. For data+. For data- r1 is 75k and r2 is 49.99k resistor. I’m using a 3a 5vdc power adapter and it seems better.
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. If you want to save money for parts and use a power supply use the one with the relay. The relay will make it work with a spst switch. I wish I knew that before ordering the parts
It uses a switching transistor to turn the buzzer on and off. It’s best to use a transistor since it can take very little current to turn on. It needs a SPDT magnet alarm switch since it has to switch the capacitor between +v and transistor base resistor. You cannot use a SPST switch. I didn’t need a transistor for the buzzer since it didn’t need alot of current.
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
Here is the birthday project of the year:
TV Arduino Video Poker machine with real poker machine buttons.
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 it doesn’t pick up keys being pressed when its not supposed to. That feature there probably made where you need windows 2000 or higher.
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 very low voltage(around 1.25v). This will prevent turning on anything on and interfering with the gain measurements. The capacitor is to remove oscillations. I used two 8 cent 10nF capacitors in series to make 5nF. All [P] switches are all part of the polarity relays. I need a 4pdt relay and a spdt relay used to provide the 5pdt switch.
How do I measure the gain?
The gain is simply
$$hFE=\frac{I_c}{I_b}$$
Where hFE is your gain, Ic is your collector current and Ib is your base current I did the math with the transistor in the circuit diagram and got around 195.
The collector meter is 50mA and base meter is 100uA
A video will soon come when the parts come in the mail
This tool checks the internet connection to see what Internet Provider your using. Good for VPNs and getting your server back online. You can use reconnect.bat file to help fix network problems or alert you when you lost connection or your ISP Name has changed. To make your batch detect first open your command prompt and find the folder where you downloaded reconnect.exe then type the following:
reconnect.exe /info
It will then give you the set of parameters that will be passed to the batch file for that connection. With that being known you can open the batch file up in Notepad and follow the instructions there. Although ip-api.com limits the number of request to 45 per minute, it is still better than the older ones in the past.
It is possible to make the computer talk by a batch file or any windows program. All is needed is a tiny VBScript file that use Microsoft Speech API OLE Object. Also all sentences passed to the command must be surrounded with quotes. Otherwise it will not sound the best.
You may download, copy, modify the VBScript file.
' delphijustin Say v1.0
' Website https://delphijustin.biz
Set sentences = Wscript.Arguments
if sentences.Count=1 then
if sentences(0)="/?" then
Wscript.Echo "Usage: "&Wscript.ScriptName&" <messages>"
Wscript.Quit 0
end if
end if
set sapi = CreateObject("SAPI.SpVoice")
For Each sentence In sentences
sapi.Speak sentence, 0
Next
if sentences.Count=0 then
sapi.Speak "I don't know what to say.", 0
end if
Circuit Simulator