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  1. duke37

    Electric Motor Help

    I would think the input black wire should connect to the black loop. This puts the two coils in parallel for 120V as Harald says in #8.
  2. duke37

    Help please

    Also country, voltage, frequency, load current or power.
  3. duke37

    Electric Motor Help

    If it is not running on DC, then how can the power supply be labelled + and -?. Some clocks with synchronous motors had a little lever which jams the motor if it starts in the wrong direction. It then bounces to give the correct direction. What do you know about electricity? Do you know how to...
  4. duke37

    Electric fencer from a 12V battery

    I still have not examined the 555 circuit in detail, however, I assume that R6/R10 controls the pulse width and R14/R15 the time between pulses. I see no need to control pulse width. You have changed R6 to R10 and R14 to R15. A better solution would be to use the higher resistor and switch in...
  5. duke37

    Electric fencer from a 12V battery

    This is getting quite complicated. I have not studied the 555 to see if it is correct. I would not include a variable for R6 for reliability, I would stick with one speed or use a switch, corrosion is a problem in fencers which results in poor connections. C3 across the SCR gate will cause...
  6. duke37

    Electric Motor Help

    Harald Thank you for the link to the motor details. It appears that the motor is a sychronous motor which will run in either direction, I have a motor in my microwave which rotates the food in a random direction. I have a sychronous motor in an electric clock which is similar. The clock has to...
  7. duke37

    Electric Motor Help

    Some small AC motors will start in either direction. DC motors will run in the direction set by the polarity. AC/DC universal motors will run in the direction they are wired. Your motor has solenoids to make the magnetic field so I assume it is an AC motor without a specific direction. To get...
  8. duke37

    Electric fencer from a 12V battery

    The 4093 is a quad Schmitt trigger so all four gates are in one chip. The CMOS series consume very little power and will run from 4V to 18V. The cost is also good. T1 in my circuit is a transformer rescued from an old TV, it my not be optimum. T2 is the only original part from the Kestrel...
  9. duke37

    doubt in active device

    It depends on what you mean by produce. Thermodymics says 'energy can neither be created or destroyed' The best an active device such as a transistor can do is to control the amount of energy taken from its input to its output, often with a lot of energy lost as heat.
  10. duke37

    0.5 volt signal to earth signal

    Kris has too much confidence in my ability. I will talk to my brother about the equipment although he is better with the big hammer than the soldering iron. Dorset is a bit far for me to drive ! And my scope is too heavy to carry on the train. The Nuffield pictured is a petrol/TVO model which...
  11. duke37

    Electric fencer from a 12V battery

    I got the transformer ratio wrong ! The 1:40 is more like an ignition coil. I am not too sure of the diffeence between a fencer transformer and an ingnition coil but the ignition coil has somwhat higher resistance and presumably will give a shorter pulse since the magnetic circuit is a multiwire...
  12. duke37

    Forum Upgraded!

    Hi Ian This is the rich text editor and seems to run as fast as I can type - if I backspace to make a korekshun, it is instant. Will rich text do greek letters? µ is OK. I am using MS Internet Explorer without addons. The reason for the bitmap file was that that is the only file type which...
  13. duke37

    Forum Upgraded!

    Hi Ian, Its grumpy me again. The speed also affects the display when typing in. I am not the sharpest but I can get several letters in before they are displayed. When editing it is a pain if the pointer takes a couple of seconds to move, I will have to learn to count. I have now tried to...
  14. duke37

    Electric fencer from a 12V battery

    I cannot read the details on the capacitor. If you are not repairing a fencer but building new, you will need to design a 1:40 step up transformer with superb insulation.
  15. duke37

    Pill box

    If you are in the UK you could contact REMAP, they may have something already designed.
  16. duke37

    Temperature compensating a transistor?

    I do not understand how the circuit works. At the least, I think the op-amp is upside down. The transistor presumably passes current depending on the base voltage. I think you should feed the base with a current not a voltage. The ICL8038 will do what you want.
  17. duke37

    0.5 volt signal to earth signal

    Spiratronics look good. In Derbyshire, there is R.F. Potts of Derby (not far from train or bus station) or Bowood of Chesterfield. Cricklewood are close to the railway station and Maplin are in several towns. CPC have no postage charge if ordered on the internet but they bombard you wth...
  18. duke37

    Electric fencer from a 12V battery

    I have repaired a few fencers in the last 45 years or so. The simplest was an HSI unit which used a valve radio 120V battery to charge a capacitor through a relay coil When the capacitor was charged, the relay dropped out and connected the capacitor to the output transformer, so starting the...
  19. duke37

    Help understanding how to best detect a small AC voltage...

    If your signal is 0.3V rms, then you will get nothing out of the rectifier due to the voltage drop. You will need to amplify before rectification. The fact that you are getting an output may be due to wrong measurement or ground errors. Is your input floating relative to the measurement circuit?
  20. duke37

    Inductor question

    You can play with the wire thicknes and number of turns but to get the same magnetic field, you will need the same power. Get as much copper in there as is possible, if this is not good enough, use silver or a superconductor.
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