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  1. duke37

    I have the qualification electronics and i don't know it's occupation

    You should have some practical experience. Start with repairing electrical equipment, this will teach you logic and how to find data. Move on to electronic equipment - clocks, radios and similar. There are usually plenty of sad cases that you can get to renovate.
  2. duke37

    LM317 2N3055 Variable Circuit Problems

    It is often recommended to place a diode across the 317T to prevent any reverse polarity which will kill the 317. If you have an AC component in your power supply, this could do the same thing. Post a picture of the bridge rectifier showing the connections.
  3. duke37

    LM317 2N3055 Variable Circuit Problems

    Do you have another digit after 1N540? Have you looked up the data? Have you contacted the Worcester amateur radio group?
  4. duke37

    fluorescent ballast replace question

    I have never known an inductive ballast fail. They often go noisy with an annoying buzz. The reason the tube will not light could be an old tube but these will often flicker before they fail completely or could be the starter which has to withstand a large voltage to start the discharge...
  5. duke37

    ltspice

    I have used ltspice very little. The accuracy will depend on the models you employ, the components are only approximations to the real world. What do you mean by accuracy? I have used 5spice as the circuit seems to be easier to enter but the free version is limited.
  6. duke37

    Can we use 5VDC LED in the AC line to show indication

    The current will be about 20mA AC. The power in the resistor will be 200*200/10000 = 4W so a >5W resistor will be appropriate. The led will pass current in one direction and will burn out when the polarity changes. One way around this is to use two leds in inverse parallel. If the fuse blows...
  7. duke37

    I need a really small, really smooooth motor...

    In a book* I once read, it said that cogging free motors were made with the armature in a helix so that as one part was pulling, another part was pushing. I do not know where these can be obtained. These are obviously more expensive, perhaps a couple of motors connected out of phase would work...
  8. duke37

    LM317 2N3055 Variable Circuit Problems

    The Worcester Amateur Radio Association meets at the scout hut twice a month. Their blurb seems indicate that they do what you want. Why not try them?
  9. duke37

    LM317 2N3055 Variable Circuit Problems

    Sorry about that, even I am not purrphekt.:D
  10. duke37

    LM317 2N3055 Variable Circuit Problems

    You obviously need some instruction, 40 years old is nothing. I am twice this and still learning. Belper is a bit too far from Worcester for me to help directly. Ben Nock in Kiddy may be able to help you find someone. You could look for the local radio club at the RSGB site. Some do courses for...
  11. duke37

    LM317 2N3055 Variable Circuit Problems

    I so no output capacitor. Can you find someone local to you to help?
  12. duke37

    Tweaking an industrial ozone generator help (HV)

    Bob is right. How are you going to make a silent corona discharge?
  13. duke37

    LM317 2N3055 Variable Circuit Problems

    Then you are using too high a voltage or your connections are wrong. If the 317T is placed on its back with the writing visible and the heat sink to the top of the page, then the connections are:- Left adjust Centre Vout Right Vin Get the supply working without the 2N3055 transistors first...
  14. duke37

    Three phase oscillator

    Elecronics is not generally done at high voltages so you will need to drop the input voltage and then amplify the output to suit. The 4018 chip can give a three phase square wave output when clocked by six times the output frequency. See CMOS Cookbook by Don Lancaster p334.. . You could...
  15. duke37

    LM317 2N3055 Variable Circuit Problems

    You are more likely to find a 270Ω resistor since it is a preferred value. red 2 violet 7 brown one 0 so 270. I have not been following the thread so will not comment on the value.
  16. duke37

    LM317 2N3055 Variable Circuit Problems

    red is 2 red is 2 red is two 0 so 2200 or 2k2 or 2.2k
  17. duke37

    Low frequency

    Please answer the question. To do this,you will need to rectify the 20MHz with very special high speed diodes or valves and then use an invertor to change to 50Hz. The invertor would be complicated if it is to generate a sine wave and even more so if it is to be locked to the mains.
  18. duke37

    how to reduce the current without changing voltage for charging a 9 v battery??

    Do not use the circuit you have shown, you will discharge whatever is in the battery and kill the power supply. Do what (*steve*) says. I suggest that you learn the difference between voltage and current.
  19. duke37

    555 output to transformer failure

    The 2032 is a lithium cell with 3 volts output. Three in series will give 9V. Putting a 3V cell across this stack will overcharge it and short the stack. Did you have a fire?
  20. duke37

    which wire?

    In the UK, double insulated cables must be used on mains supplies. Thus there shoud be insulated twin wires surrounded by an insulated sleeve. So called bell wire is not adequate.
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