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  1. Miguel Lopez

    Instability on a diferential output amplifier

    Hello I've been trying a diferential output amplifier, as it is my intention in the future to build a transistor oscilloscope, with better performance that the valve one that I'm currently using. Althought the circuit that I've been testing amplifies the input signal very well, it suffers from...
  2. Miguel Lopez

    Building my own bench drill

    The turner finished the anular pieces that I need to build the sliding piece. Here a picture of them, inserted in the pillar. The caliper is opened at 10 mm to give an idea of the dimensions.
  3. Miguel Lopez

    Building my own bench drill

    Hi Minder That would be for a very sofisticated drill, which is beyond my reach. The drill that my old man built has a single pulley and an AC motor, so, only one speed, and so will be mine. I have used it that way for a lot of years with good results. The only diference will be that I will use...
  4. Miguel Lopez

    Building my own bench drill

    Don't be so sure :confused:. I have not noticed any change in our normal life since 2014.12.17. Maybe on higher level, but for the "Cubans on feet", life goes on. Anyway, I have nothing to lose trying it, and a lot to win, so why wait? :)
  5. Miguel Lopez

    Building my own bench drill

    Hello everybody As this project is not exactly electronic, but electro-mechanical, I think that this is the best place to post it. The thing is that since I remember, I have used a bench drill that my father built. The bench drill is one of the electro-mechanical tools that I use most of the...
  6. Miguel Lopez

    Clock in multisim

    74LS92 can be used. But for a digital clock it is not the best choice. For minutes and seconds counters, I suggest you to use 74LS90 or CD4518. CMOS is always a better choice, cause when it is battery-run, (in the case of power failure), CMOS demands less current than TTL (and I mean REALLY...
  7. Miguel Lopez

    Back from the Dark Side

    Hello again to everybody After several months off-line, I'm back again at Electronics Points. It seems that I was in the Dark Side, so my IP address was not allowed to connect to the server. It seems that is something related to our Northern neigbourg. Hope this situation has solved forever...
  8. Miguel Lopez

    Homebuilt Signal Generator

    Thank you very much for your compliment HellasTechn, I do my best. Finally, here the SigGen in its final location (above my DC PSU), in my messy workbench, while testing a valve circuit. Have to say that the Amplitude Modulation section is not built yet, as I will begin my experiments on AM...
  9. Miguel Lopez

    Homebuilt Signal Generator

    Here is how the SigGen cabinet looks like with all the modules inside. And this is the front panel
  10. Miguel Lopez

    Homebuilt Signal Generator

    My source of components is scavenging old equipment mostly, so I don't think that I would be able to find something like that. Thanks for the advice anyway, Who knows. Does the Embargo allow you to do that?
  11. Miguel Lopez

    Homebuilt Signal Generator

    How can that be done? I think that should be better once finished. ************************************************************************** Resuming thread. I want to share some pictures of the LF section. As I said before, I switch the ranges by changing the capacitors in the circuit of...
  12. Miguel Lopez

    Homebuilt Signal Generator

    I can't. There is nothing like that here, and I lack the required knowledge to work with it. I built the fixed frequency sections using the same circuit as for the LF and HF sections respectively, and I adjusted them in the lab, using a very accurate standard. I know they will have some drift...
  13. Miguel Lopez

    Homebuilt Signal Generator

    I tried that some time ago, and I found that it needs a lot of electronics to get what I want, so, I think that this is the simplest way. Am I wrong? Well, for the high frequency section and the 465kHz fixed frequency output I used the following circuit: It is a version of the circuit found...
  14. Miguel Lopez

    Homebuilt Signal Generator

    Hello everyone The need for a signal generator in an electronics workbench is out of discussion. I built a tiny signal generator in the past, that I've been using till now. It is very limited as it gives up to 50 kHz of sinewave. It has been very useful but now I need something else. My...
  15. Miguel Lopez

    Current Limiter Circuit

    Check this: http://www.radio-electronics.com/info/circuits/transistor_current_limiter/transistor_current_limiter.php
  16. Miguel Lopez

    Multiplexer IC for analog inputs

    Use an OpAmp as adder and ground the undesired inputs with a digital mux
  17. Miguel Lopez

    Audio/Video to RF. Help!!

    It is analog signal. Don't worry, I have desisted on this effort due to lack of knowledge and parts (and suitable equipment). Thanks anyway
  18. Miguel Lopez

    Help with aerial for channel 38

    That is exactly what I intend to do. Thank you for your advices Dave, I will talk about the results when I try it.
  19. Miguel Lopez

    Help with aerial for channel 38

    Pictures are in Post #6. I have not made any change in the aerial until know what to do first. I want to make changes as with the original design (the one in the pictures) I have noticed that signal level in the TV set has decreased. That's why I want to make changes to increase gain.
  20. Miguel Lopez

    Help with aerial for channel 38

    The aerial is working but gain has decreased. You should probably be right as temperatures are hell-like by these days in Cuba. And humidity is always high. Signal is lost most of times when it is rainning.
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