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Everything posted by Dido

  1. AN920, thanks for your comment :) I decided to build the second circuit the one using a crystal oscillator, I have got another question, I think that I will need a frequency counter in order to adjust the trimmer capacitor to the right value, what`s the use of SA in this circuit: I can`t understand the table drawn in the bottom of the picture. What are the two CD4040 for?
  2. Hello, I want to make myself a digital clock using LED displays as readout, I`ve been searching for some schematics of clocks, there are lots of such in the internet, but I still couldn`t find a reliable one. I don`t want to use a microcontroller, I want the clock to be made with CMOS or TTL IC`s. I found a German website where I found lots of digital clock circuits http://pitts-electronics-home.de/electron/schpluhr.htm I want to make the circuit Schaltplan einer 6 stelligen LED Digitaluhr mit CMOS- IC's, I have a few questions about this circuit, as it will use a 555 timer what accuracy should I expect?, Is this circuit going to work?
  3. Dear friends, I have built many times the LED Display Digital Voltmeter project and it works pretty fine. Now I want to build myself a Digital Thermometer using this voltmeter, but I want to use seven segment Vacuum Fluorescent Tubes instead of using LEDs. I have a small problem in constructing the driver for these tubes as they use 30V for the segments to be lit. I am thinking of using PNP switching transistors which will drive the tube`s electrodes. I can`t figure out which will be the best transistor to use for, have you got any ideas? Can you tell me if you have more practical and convinient ideas for the driver? I am attaching you the datashees that I found in the internet, the tubes are russian make, I have got a whole bag of these tubes and I want to make it with these as they are very bright and easily to be read. I hope that there will be someone who can give ideas. Regards: Deyan Dimitrov
  4. Hi, I am planning to build myself an electronic clock with a big and bright LED display. I looked over the net and I found out that the schematic that I have attached is the perfect for me and I just thought that you`ll be interested in it too. The only problem I have is that I can`t find a scanned PCB of that project.It`s DIY kit No 73. I`m a little lazy and I don`t want to spend hours and hours over the PC drawing that PCB, so can anyone tell me where can I find that PCB and download it? You can find more info for that kit at http://shopping.netsuite.com/s.nl/c.317485/sc.8/category.44/it.A/id.445/.f k73.pdf k73sch.pdf
  5. I opened my camera but I haven`t tried propanol I tried blowing on it ant it worked now I haven`t got any problems at all but I am stiill not sure about propanol. I think that it is suitable for heads or other devices but it is not suitable for optics and optical devices. ??? ??? ???
  6. hi prateeksikka are you sure about propanol? have you ever had such a problem? ???
  7. Hi Trigger, as you can see he is talking about a digital meter, and the meter won`t blow if you short circuit it`s supply so this is not the problem. BTW: there are analogue meters which can measure both positive and negative
  8. Hi RDL2004, If you have shorten the 5 V supply then the meter shouldn`t have blown up, maybe there is wrong something else, try to investigate all the circuits maybe something has unhooked.
  9. Hi badai, Some printers have such possibilities to print in a mirror mode, this depends on the driver you use and of course the additional program that you have installed with your printer. Myne is Epson C82 and when I print for myself PCB`s I just set it to mirror mode from the preferences menu. 8)
  10. What do you mean with that 20K nanometers?
  11. Hi Ante, Trigger I have opened my camera I even dismounted the lens and when I saw that I`m inexperienced working with optical devices such as object-glass, lens etc.... I pieced it together again. I went to the local service and he told me that he can`t do anything with my camera because he hasn`t got the proper tools. I think that I can do it myself, I`ll try blowing with a pump on it first. I won`t even think to wipe the dust because I`m sure that I`ll scruff it more.
  12. I`ve got a problem with my digital camera and It really freaks me out when I see that the photos are miserable and scruffy. ;D So let me explain you the real problem. A month ago I realised that when I shoot a picture and then I view it on my PC I see two spots on the picture. The first spot (the big one) looks like a very small fine hair, so I thought that there is dirt on the lens I cleaned the lens but this didn`t help then I searched in the net about that and I soon realised that there is dirt on the CCD sensor of the camera. I understood that this is a common problem in new cameras. I found sites which explain how to clean your sensor but I`m not sure that I can do that with home tools. Have you ever had such a problem? Look down at these links maybe you`ll understand better what I mean :o http://www.cleaningdigitalcameras.com/ http://www.pbase.com/copperhill/ccd_cleaning http://www.bythom.com/cleaning.htm
  13. Look at these links they might be useful ! ;D ;D ;D http://www.quatech.com/support/comm-over-isa.php http://www.quatech.com/support/comm-over-mca.php http://www.quatech.com/support/comm-over-pci.php http://www.quatech.com/support/comm-over-cpci.php http://www.quatech.com/support/comm-over-pcmcia.php http://www.quatech.com/support/comm-over-usb.php
  14. 1. Visual Basic 2. Quick Basic 3. Borland Pascal
  15. The difference b/w an ISA slot and a PCI slot is that ISA slots are 16 bit and PCI slots are 32 bit. ISA slots are used in old computers thay are long usually black coloured but you should know that ISA slots are no longer manufactured.For more info try to search in google or sth.
  16. Hi I can`t find the datasheet for LC8922 IC I`ll be very grageful if you can help me! :)
  17. I have a problem with my DMM. I OverVoltaged it It can mesure up to 1kV I measured maybe 5kV with it. Now It displays on the 3.5 LCD Display just the number 1 whatever I try to measure Ohms Amps Capacitance frequency etc... I opened the multimeter and I saw nothing interesting there five or six Op-Amps a main chip made on the PCB board which I most probably think that is the ICL7106 - this is an analog to digital converter, lcd display driver, there are although some analog circuits inside there. I want to ask you Is that IC the problem (I think it is) I`ve attached the schematic see it nothing else I just want someone to advise me should I try to change the IC or throw it away.I think that if I change the IC it will most probably work. Maybe I`ll have to tune it up a little. ???
  18. I`m planing to do this project I read your discusses ::) and even now I can`t understand if the PCB given here in the article is OK I hope so beause I`ve already etched it.
  19. Try to make a full repair (not reinstall) just repair that`s what I usually do. Windows XP is rubbish all stuff which iz made by Microsoft iz junk
  20. Here Is the circuit I`ve been using for one year.The mosquetos can`t got used to is because I`t changes It`s frequency all the time so the mosquetos can`t get used to it It`s efficiency is better in dark areas. for the beeper you can use beeper 400ST - a 40Khz working frequency for the repellant D1D4 - 1N4001. R1 - 3.3 М, R2 - 680 к, R3 - 10 к, R4 - 3 к, R5 - 4.3 к, R6 - 4.7 к, R7 - 5.1 к, R8 - 1 к, R9 - 15 к, R10 - 910 к, R11 - 1 к, R12 - 9.1 к, C1 - 330 nF, C2 - 150 pF, С3 - 100 F/25V. For the PSU R13 - 360 к, R14 - 56 /0.5 W, C4 - 330 nF/400 V D6 - Д814В. All you need for making this project is in the zip :P Insect.zip
  21. Ha Ha Ha I found that chip for 5 minutes looking in google Try looking for 2T6551 I found the datasheet for 2 minutes.
  22. Look at that one The design shown will test PNP and NPN transistors, diodes and SCRs both "in-situ" (equipment of course de-energised) and also by direct connection to a stand-alone component. It is a simple GO/NOGO test which can identify diode and transistor action and will indicate diode polarity and transistor type PNP/NPN, if this is unknown.
  23. I have heard about this but I never thought It was true. Do the Solar Cells have the same working structure ???
  24. sasi why don`t you try this link http://w1.859.telia.com/~u85920178/left_pcb.htm :-[
  25. Ante don`t worry the electrolyte consists of Sulphuric Acid and distiled water the standard is 60% Sulphuric Acid and 40% Water of course different manufacturers add other chemicals to lengthen the life of the battery.I should be more worried when I start the electrolysis process because there are fumes that evaporate these fumes are very dangerous for the human beings and also hydrogen which is evaporated can be dangerous because it can explode if it`s quantity is more. You know I don`t like this way of making PCB`s as you say it`s more dangerous.I use many chemicals in my lab I make fluxes and other interesting ventures. Here is a photo of my glass-ware - a little messed up in the ceiling. :P
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