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  1. duke37

    Control alternator voltage back to 6vlt battery?

    If the headlight is on all the time the engine is running, then perhaps the bulb is not powerful enough to limit the voltage. If you use a Zener diode across the battery, then it will need to be powerful and have a sharp knee so that it does not discharge the battery when the bike is not being...
  2. duke37

    Control alternator voltage back to 6vlt battery?

    12V cars are usually charged between 13.8V and 14.4V. It is necessary to use as high a voltage as possible without gassing. A 6V system should be charged at 7V. You should never have to charge the battery if you use the motorbike once a week or so. I have just changed my 12 year old car battery...
  3. duke37

    How is a brass gear removed from a DC motor?

    And ruin any oil lubricated plain bearing. Use the bearing puller in the groove you have already made. You can get nut spltters and it should be a doddle to split brass.
  4. duke37

    Control alternator voltage back to 6vlt battery?

    I am not familiar with small motorcycle generators but have a vague memory that they have a constant current output, It should be possible to restrict the voltage to 7V by adding a load such as the headlights when the current is too high. I do not see how to maintain 7V when the generator is...
  5. duke37

    Cavity resonator - construction?

    Cu/Zn is brass. There is coupling between the input and output wires via the resonating central rod which is tuned by the variable capacitor at the end. The size can be reduced with some loss of Q by changing the central straight rod to a helical coil. Constuction from copper would be a bit...
  6. duke37

    Make a flow switch from a hall-effect flow meter

    I have already said it.
  7. duke37

    Make a flow switch from a hall-effect flow meter

    I am old school and would use a charge pump to give a voltage proportional to pulse rate. Use a comparator to determine whether there is sufficent flow to switch. Use positive feedback to give a deadband to prevent unneeded switching.
  8. duke37

    decreasing wave frequency with sbl-1 mixer

    10kHz will be output with either 3174kHz or 3194kHz. The coil will not have a high enough Q to distiguish between these. The long wires will enable lots of interference to be received. Such a circuit should be installed in a screened box with an RF input and a feed through capacitor on the...
  9. duke37

    decreasing wave frequency with sbl-1 mixer

    You have shown a block diagram, not a schematic. If the Butterworth filter uses active components, then they could introduce noise. What was the scope measuring?
  10. duke37

    Heating Belt for Brewing

    The UK used to be 240V and some european countries were 220V. The UK has not changed in practise but follows the european standard which is now 230V +10% -6% that is 216.2V to 253V I get 240V consistently Presumably the standard was made wide enough so that no distribution equipment needed to...
  11. duke37

    decreasing wave frequency with sbl-1 mixer

    The noise must be comming from somewhere. If it occurs with the input signal shorted, then it is due to the heterodyne frequency. This should be clean and preferably a square wave. Do you have interference at about 6MHz?
  12. duke37

    Console "E1". Water damage? Found capacitor leg jacked. Replaced still E1

    Solder runs towards the heat so you should put the solder on the hot joint not the iron. You may need a little on the iron to just wet it and so conduct the heat to the joint. Putiing a blob of solder on the iron and then transferring to the joint does not work. 60% tin and 40% lead is correct...
  13. duke37

    Console "E1". Water damage? Found capacitor leg jacked. Replaced still E1

    Your soldering does look rough. Remove all the old solder with a solder sucker or fine braid with flux. Make sure there is no connection between the trace and the adjacent circuit. Resolder joints with cored, leaded solder using a hot iron with a good sized tip. Heat the joint and then add...
  14. duke37

    'Frosting' on top of Ni-Cd batteries

    Ni-Fe batteries will produce sodium carbonate fuzz.
  15. duke37

    One way dial/push dial to prevent user from switching device off too fast.

    You can get time delay relays that could keep the device energised for a time. Even a resistor/capacitor/fet system could do this.
  16. duke37

    Question storage dvd media and ziplock and silica gel

    The zip lock bag will not have a good seal, there will be an opening at the end of the zip and variations in air pressure will allow damp air to enter. I suggest using a plastic food box with a lid which has a seal and is clipped on. There is no need to get the gel close to the DVD, diffusion...
  17. duke37

    Question storage dvd media and ziplock and silica gel

    The silicon gel should be held inside a sealed container, a zip lock bag is not likely to be good enough. Any moisture inside the same container will diffuse to the gel and keep the contents dry. You may have to regenerate the gel often if the contaiiner is not fully sealed.
  18. duke37

    questions silica gel old

    If you look on Wikipedia you will see that the blue silica gel contains a cobalt salt which is not heathy so do not eat it. The colour will tell if the gel is saturated with water. You could experiment to determine the number of useable cycles. My guess would be about a thousand.
  19. duke37

    questions silica gel old

    The moisture is absorbed in the gel structure so will not leak out. The moisture is liberated if the gel is heated so the sachets can be dried in an oven.
  20. duke37

    Off grid house lighting

    I doubt if there are regulations for running cables at 12V but the wires must be thick enough to keep voltage drop low and the cables should be labelled so that they are never connected to the mains. Remember that a battery can supply sufficient current to start a fire so use a suitable fuse. A...
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