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  1. crutschow

    CDs go silent occasionally

    Does the CD player have an external audio input?
  2. crutschow

    Flyback + Cap charging time, help

    A normal AC transformer uses the magnetic core to transfer the energy from primary to secondary with the turns-ratio determining the primary voltage to the secondary voltage.. It never stores any significant energy as the inductance is just to determine the value of the small magnetizing...
  3. crutschow

    How long will a 0.9ma nano motor unit last on a DCell?

    A good alkaline D-cell has about 18,000 mAh of capacity, so you divide that by your motor's current (0.7mA or 0.9mA as the case may be) to get the maximum life of the battery (it would be around two years).
  4. crutschow

    Flyback + Cap charging time, help

    That's true if the current is continuous, but you said it was pulsed, so you need to take the pulse-width and its duty-cycle into account.
  5. crutschow

    CDs go silent occasionally

    I would try cleaning the head.
  6. crutschow

    Volume Control for Quartz Cuckoo Clock

    The simplest probably would be to connect a pot (say 20-25 ohm) in series with one of the leads going to the speaker (pot connected as a rheostat: one connection to one end of the pot and the other connection to the wiper).
  7. crutschow

    Exceeding rated current for power input connector

    If your maximum is 11.5A then I think it would be safe to use one of the 11A sockets that bertus suggested, although the socket may get a little warm in use. If you use no smaller than 14 gauge wire from the socket to your circuit, you should be okay.
  8. crutschow

    Exceeding rated current for power input connector

    Since all the available 5.5x2.5mm sockets are rated at no more than 11A, I suspect that the plug the power adapter manufacturer used is overrated at that current. It's likely also rated for no more than 10-11A, but the manufacturer used it since it was a cheap, common DC power plug. and they...
  9. crutschow

    Exceeding rated current for power input connector

    If the socket is rated for 10A maximum, what makes you think the jack on the power supply will carry 20A?
  10. crutschow

    Exceeding rated current for power input connector

    Using a 10A connector at 20A could result in overheating of the connector and possible failure Also the voltage drop at 20A may be more than you would want.
  11. crutschow

    Best op-amp for audio use?

    TL071 single, TL072 dual and TL074 quad are good choices. Another popular choice is the NE5532.
  12. crutschow

    Is this possible to do?

    Below is the LTspice simulation of a circuit that should work for you using two colors of the tri-color LED. The blue LED draws about 2mA when the phone is on-hook [green trace low], (which shouldn't affect the MagicJack operation), and the red LED draws about 10mA when off-hook. (Note that this...
  13. crutschow

    Is this possible to do?

    Need to know how the LED connects internally to the leads.
  14. crutschow

    Adding pre out on soundbar for sub.

    What do you use as the sound source to the soundbar: RCA analog, optical, or HDMI?
  15. crutschow

    Toggle Switch with relay

    What is the value of the DC voltage from the diode bridge? Another option is to use a CMOS flip-flop IC, such as a CD4013, to provide an alternate action from a push-button. Also I have a circuit that uses two MOSFETs in a bistable configuration.
  16. crutschow

    Very thin wire in an ac motor?

    Yes. For a small motor to operate from 240Vac, the field coil inductance must be very high to minimize the field current and keep the core from magnetically saturating, which requires a lot of turns. To get a lot of wire turns around a small coil requires the use of very thin wire.
  17. crutschow

    MOSFET not giving sufficient power

    Yes, I missed that. But changing R2 to 100Ω means the Arduino output must sink 120mA, which it can't. My suggestion is to remove the 1kΩ resistor from gate to ground or increase it's value to about 100kΩ. That will still be sufficient to pull the gate low with a floating input.
  18. crutschow

    MOSFET not giving sufficient power

    R2 should be 10kΩ, not 5k.
  19. crutschow

    MOSFET not giving sufficient power

    Below is the LTspice simulation of the circuit Harald suggested:
  20. crutschow

    MOSFET not giving sufficient power

    Those curves show a "typical" characteristic (likely for a Vgs(th) of 3V). (You should never design a circuit using typical characteristics). The particular MOSFET you have would have a current less than 2A at a 5V Vgs if its Vgs(th) was the 4V max value.
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