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  1. Minder

    Help with a Float Switch circuit.

    One side of the coil of the relay is OC, it will never operate as shown, where is it fed from? M.
  2. Minder

    Help with a Float Switch circuit.

    Looks like you need 12vdc relays, the convention is to use 0 & 12v not +12 & -12 as this implies a dual supply. Also you show one relay coil open circuit? M.
  3. Minder

    clever vibration motor driver?

    Here is an original promotion of the 2n7000 when it was launched. M.
  4. Minder

    clever vibration motor driver?

    In the motion control and servo world the analogue drive is seldom if ever seen, practically all manuf use PWM now, the PWM modules in Pic's make it relatively easy. http://tahmidmc.blogspot.ca/2013/01/using-high-low-side-driver-ir2110-with.html M.
  5. Minder

    capacitor plate voltages

    It happens all the time in many different circuits, when passing an AC portion of a signal for e.g. I assume the voltages you show are a DC source. If electrolytic, the polarity must be observed. M.
  6. Minder

    clever vibration motor driver?

    It is done all the time, the simpler method is SCR bridge and that has a switching frequency of 100/120Hz. With PWM a switching frequency of 4Khz and above is considered a a quiet enough solution. In fact there are many sold on ebay designed around the 555 and go for around $5.00 . M.
  7. Minder

    Need help finding a replacement transistor?

    There is a 2SB828 that may be the equivalent? http://rtellason.com/transdata/2sb828.pdf M.
  8. Minder

    clever vibration motor driver?

    If using a μp controller, why not use one that has a PWM module built in, much simpler and more efficient than Analogue. M.
  9. Minder

    Just learning the ropes

    It also changes the reading format if the scale PB has been locked in to Manual Ranging, non Autorange at that point.;) M.
  10. Minder

    Noise resistant microcontroller used in high power inverters for PWM generating

    The Picmicro 18F and up series have built in PWM modules isolation can be done with HS optoisolators if neccessary. Is this for IGBT or Mosfet design? M.
  11. Minder

    idle: driving steppers closed-loop?

    Maybe a patent on certain Firmware/Hardware, but certainly NOT on the concept. Most D.Top CNC use steppers open loop because of cost, the attempts for closed loop do not appear yet to come close to the resolution of a servo PID loop, some have addressed it by using fractional stepping but this...
  12. Minder

    idle: driving steppers closed-loop?

    I have picked up nice high quality BLDC on ebay such as Tamagawa, Aerotech, and Applied Motion etc, the controllers I use output analogue ±10vdc and I use Copley or A-M-C drives. The motors all come with differential encoder and commutation tracks. M.
  13. Minder

    idle: driving steppers closed-loop?

    I use BLDC in preference to steppers in servo positioning systems for quite a few of the obvious reasons already stated. There have been many attempts in the past to achieve near servo PID loop performance from steppers, some fairly successful , but so far I have not been tempted to change over...
  14. Minder

    Help with transformer from edu

    That appears to be a ferrite core choke or inductor. Is there 2 windings or just the one? M.
  15. Minder

    What is the basic software for designing Schematic and PCB's

    One that is free and can compete with Orcad IMO, is Kicad. From create schematics to Gerber files for board production. There are a great many tutorials also. M.
  16. Minder

    Wiring for a raise/lower motor

    Then the #2 should work, incidentally you can also wire it with the Battery pair and the Motor connection pair transposed and it will still work. M.
  17. Minder

    old garage door opener circuit board

    1-2-3 terminals appear to be from a CT secondary, you normally would expect an identical AC voltage reading from centre to each outside winding. (2 being the CT). I assume the voltage will be 19v 0 19v? 6&7 AC power input. 4&5 just mounting tabs. M.
  18. Minder

    Wiring for a raise/lower motor

    If orange and blue are the motor wires. It would help to identify the actual source of the conductors and their colours. Power supply and motor. M.
  19. Minder

    Wiring for a raise/lower motor

    Like so. You need 3 posn toggle, with centre off. Presuming a DC motor. M.
  20. Minder

    Make electronics : experiment 8 problem

    I agree, the circuit does not make alot of sense? Where did you come up with the circuit? Also the relay part No is a 5v version, instead of 12v. M.
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