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MP
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Posts posted by MP
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ginji, thanks for the update on the project. I would also be interested in an easy method of building transformers if your dad would not mind sharing. There is a post and an article on this website but it is very difficult. If you could do this, please add as a new post so that the subject is easily found by others.
Thanks!
MP -
Billy, that is a very clean looking board from press-n-peel. I tried this method when it first came out and it was not very good. It appears that it is working much better than what it used to.
Nice board!
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Jandro,
Did you find a solution?
MP -
I used to have an old Texas Instruments computer that had no storage such as hard drive. Everytime you wanted to run a program, you had to write it, then compile it and run it. It was a TI-99A. Ever seen one of these?
MP
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I have several different vintages myself. A couple of XTs, one 286/20 MHZ, a 386/40 MHZ, a 486 not in use as it is too troublesome, one 586/133MHZ, which came out just before the Pentium, a Pentium 200MHZ,then I have the P2/300MHZ, P3/450 MHZ and the one I use the most is a P4/3 GHZ. The XTs are only used for some old programs, eeprom burner and some CNC work. The others take their turns as CNC drones as well. The P2 and P3 have different OS and serve to work well with different programming languages. All except the XTs are on a network and all can access the net. The P4 is used for designing and programming as well as most of the Internet work. Although the others work fine, I have found that there is nothing that compares to being able to listen to mp3s, surfing the web, having more than one cad program open and a spreadsheet going all at the same time with no loss of speed. When I click on something, I immediately see it. I do not wait for it to load.
However, I use my computer for work, so time really means a lot to me. The good point to having multiple computers is that you can access what you want on a network without running back and forth between the shop and the house or keep back ups of all of your programs on more than one system in case you have a major crash.
MP -
1N5338 is a 5.1 Volt Zener rated at 5 Watt. (5 volts X 1 Amp = 5 Watts) You have to go with 5.1 or 4.7 volts. You cannot get 5 volt exactly. Also, note that this has a 5% tolerance.
You will have better current availability if you use the zener to control the base of a power transistor. (in this case you will not need one rated so high).
MP -
...except with this TTL circuit you are not worried about slew rate as the response time is only dependent upon the response of this transistor at saturation. This is plenty fast enough for TTL switching.
MP -
You will also have to provide the gauge of the wire to determine the resistance. Resistance can be determined with these two known values (thickness or gauge and length).
MP -
I think any kind of remote controlled device is pretty cool. If you can make it self powered without the cord, that is even better.
MP -
You should post a link to the project in your post so that we do not need to leave the forum to go look. Otherwise, we will have to log back on and find your post again.
MP -
http://www.cadsoftusa.com/
You can download the free version. It will output to a graphic image file.
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yourwins, the article mentions the knight rider lights, so I would assume that it is what you want. In a little more searching I find there is also a knight rider circuit on our site:
http://www.electronics-lab.com/projects/motor_light/035/index.html
Then also here:
http://www.charlton.vic.edu.au/mark/electronics/555_projects/k-rider.html
...and here:
http://www.talkingelectronics.com/FreeProjects/555/555-P3.html
They all seem to be similar. Let us know if it is true that none will give you the knight rider effect as the authors claim.
My own favorite circuit would be to use a microprocessor chip.
MP -
Yes, ante brings up a good point. A good addition would be an isolation transformer. A 1:1 transformer or a similar circuit that would not change your voltage but which would guarantee that you are isolated from the mains. This isolation might even help with the problem you are seeing, depending upon the circuit of the variac.
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Here is a link I have found regarding making your own capacitor. All done on a breadboard. It is very introductory but causes one to form other ideas as well.
Have fun!
http://www.doctronics.co.uk/owncap.htm
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Ian, newbie questions are always welcome.
MP -
Ian, do you really need this old technology? Mixos has posted a diagram of the current meter and voltmeter connection on page 2 of this post. This is with the 7107 IC, which will give you a much better digital display. Just a suggestion.
MP -
John, I am sitting here chuckling as I visualize the mower running over the power cord... ;D Oddly enough, most people have this problem with an electric push mower while they are pushing it.
Perhaps we will see some ideas for the remote control version. Is it a gas mower or electric? A gas mower has the possibility of running an inverter for the power to the push motors. Then maybe RC for the control?
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saileshkrishna, in fiber optics many signals are multiplexed together then sorted out at the other end by a few different methods. One method is digitizing the signal and demultiplexing at the other end. Another method is to use different color filters at the other end to separate the different wavelengths. I have not had experience with long range ultra sonic transmission, but I think that if you can get a good signal to go the distance, the method would be similar. Multiplexing and demultiplexing the different frequencies within this spectrum such as multiple channels.
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It is here:
http://www.aaroncake.net/circuits/chaser.htm
MP
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Hi ante. To add to this:
Yes, this is mostly dependent upon the voltage available. (but of course voltage does not move without current) As we see in a solar panel charging a 12 VDC car battery, there is not much current coming from the solar panel, but the voltage is normally around 20 VDC when not connected to anything. When connected together, the battery then pulls the solar panel voltage down to it's voltage potential and the solar panel gives the battery some charge.
This is only able to work because the solar panel continues to convert light to energy. If it were just a storage container, it would just be drained by the large capacity of the battery and become useless.
I am curious to see how these crystals work in this scheme. I am assuming the use of crystals might be what is called a trickle charge?
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There are many reasons you might have noise. Do you have the schematic? Sometimes a picture of the circuit is also useful.
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There are problems with that analogy. You are missing the point and becoming argumentive. I am not going to waste my time arguing with you about this simple amplification circuit. As with my other post, if you have something to offer here, then build it. If all you have is theory, put it in the theory category. Because so far, all you have offered is theory. If you want to offer a different design, draw it out and post it.
It is simple.
MP -
kyriakos, what changes were needed in the schematic?
Since you tested the circuit with several different display types, it would seem that the code is not correct for 4 bit display communication. Had you not tried other display types. my first guess would have been that you have one of those 16X1A displays.
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This area speaks of projects. If you build a project and find mistakes, please let us know the corrections so that changes can be made to the original. If you just want to theorize what might be wrong or what does not work, I think that is a subject for the theory articles area of the community. I think what is needed in this area is proven design change. Nothing can be accomplished here if you will not put forth the effort to build it.
MP
Light Switch
in Electronic Projects Design/Ideas
Posted
Not very effectively. The LDR will be fighting the trim pot with a parallel resistance. What are you trying to accomplish with this circuit? A variable power source dependent upon light?
The center leg of the 78XX series regulators are meant to be at ground potential for the rated voltage. If you lift them above the ground potential, then the voltage of the regulator is higher. For example, if you were to connect a diode between the middle leg and ground on a 5V regulator, you would be 0.7 V above ground potential and thus would have a 5.7V regulator.
I hope this helps.
MP