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  1. gjones33

    microcontrollers in the classroom

    Hi all, For what its worth, as an educator I chose the 8-bit PIC family I received excellent support from Microchip and with only 35 instructions to learn it was easy to teach. PIC microcontrollers are also well supported in hobby magazines and there are plenty of resources for students to help...
  2. gjones33

    Inductive load

    Hi all, Please be careful with variable transformers and do not place isolation transformers or other inductive loads in the primary circuit. It is often forgotten that a variable transformer can also act as an auto transformer with a ratio of turns below the tap to the turns above the tap and...
  3. gjones33

    Capacitor Charging- Where are all the electrons?

    Hi all, I suggest it is physically impossible for any naturaly occuring mechanisim to exert a force of attraction with inverse square law characteristics.No one has ever succeeded in constructing a mechanical model with these characteristics. Cheers G
  4. gjones33

    Capacitor Charging- Where are all the electrons?

    Hi all, Oh dear how good our education system is at indoctrination. Of course I am not saying energy is not dissipated in sparks, radio emissions or heat. What I am saying is that in the first instance these losses can be minimised to almost negligible values as in other experiments, secondly...
  5. gjones33

    Capacitor Charging- Where are all the electrons?

    Hi IRstuff, I disagree. In potential / kinetic energy conversions as in a pendulum, for example, both energies can be measured at every stage from zero to 100% less losses which, in a well designed experiemnt such as a clock can be very small indeed. Not so with the capacitor experiment over...
  6. gjones33

    Capacitor Charging- Where are all the electrons?

    Hi electricpete, In the capacitor experiment it is not compulsory to use a switch or low value resisitor. Modern capacitors have very little leakage over relatively long periods of time and therefore a high value resistor can be used to limit the maximum current and radiated energy to levels...
  7. gjones33

    Capacitor Charging- Where are all the electrons?

    Hi Cbarn24050, Why use non-polarised capacitors? The radiated energy can be measured easily and accurately with a good quality oscilloscope. An experiment with 2 x 10,000 mfd capacitors charged to 150 volts will show a loss of about 6oj and that is easily detected. Try discharing the...
  8. gjones33

    alternator as a generator in a car

    Hi bjc, The loads you mention - compressor, tv, hand tools etc are all low power less than say 500w or about 2 amps at 240 volts which is a lot less power than the 10 amps you mentioned originaly. You might get away with running the engine on a fast idle speed at these low powers but the speed...
  9. gjones33

    alternator as a generator in a car

    Hi Birt, Ayrboy is quite correct and throwing a 3kw load on the engine will reduce the speed and therfore speed control is essential. For saftey reasons this is definately not recommended. An alternative might be to obtain a separate small i.c engine say about 7 or 8 hp Cheers G
  10. gjones33

    Capacitor Charging- Where are all the electrons?

    Hi All, First of all let me correct the erroneous explanation given in text books about the vanishing energy. I have conducted this experiment with very large value capacitors and high voltages with automated set ups to try and find the heat that is supposed to be produced and I have not found...
  11. gjones33

    A Circuuit to Drive Ultrasonic Transducers

    Hi mmartens, A simple and inexpensive solution would be to program a microcontroller to provide the frequencies you require. Cheers, G
  12. gjones33

    Capacitor Charging- Where are all the electrons?

    Hi Guys, What an interesting an instructive series of posts leading to Electricpete's vanishing energy. If the two capacitors have the same values then, within measuring tolerences, exactly half the energy is "lost" each time a capacitor is charged and connected to the second...
  13. gjones33

    mains power from car alternator

    Hi Colinh, I have known of automotive alternators being re-wound for 240 volts and used as a mobile power source for welding applications. Most alternators have 12 poles which means they produce 6 cycles per revolution. At say 1500 rpm this gives a frequency of 150 hz Cheers, G
  14. gjones33

    Medical Blower Motor source

    Hi JohnSP, Try Litton Poly-Scientific on 800 577 8685 x222 or 800 577 8685 x 256 Cheers G
  15. gjones33

    dc motor starting with high load

    Hi garyp, In reply to your question, yes, you could put a capacitor in parallel with the supply BEFORE the motor start circuit. The capacitor would then be charged before you start the motor and provided it is of sufficient capacity it would hold the voltage up during starting. As a rule of...
  16. gjones33

    synchronous machines in the chemical combinat

    Hi Hakla, Can the pistons be staggered so that they do not all reach their maximum power requirement at the same instant. Cheers, G
  17. gjones33

    555 tips, fixes, and cures

    Hello Otaio, For reliable operation d.c operated relays should have a small air-gap between the magnetic pole pieces otherwise the magnetic field may not collapse after the current has been removed. A piece of sellotape over the pole piece should suffice and this will have no effect whatsover...
  18. gjones33

    Encapsulating/potting pcbs

    Hi all, Does anyone know of a company that encapsulates small pcb circuits? Thanks G
  19. gjones33

    Electric diagram

    Hi vikonin, Another source of free trial software with a good electrical library is Smartdraw. http://www.smartdraw.com/ Cheers, G
  20. gjones33

    DC Motors in Oil

    Hi sdk, Our drives can drive standard stepper motors as both stepper motors and efficient, sensorless, high speed, high torque bldc/servo motors. Our drive is a lot simpler and a smaller package than bldc hall effect drives and does not use pwm or variable supply voltage. Dynamic braking (not...

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