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  1. crutschow

    Hp power use

    The inertia of a steady load has no effect on the power, only the energy required to get it to speed.
  2. crutschow

    Hp power use

    Did you install a new pump with motor or just a new motor? The power drawn by a motor is basically determined by its load and wouldn't change much with the motor rating for the same load. You electric bill will be mostly determined by the amount of water you use, not the size of the pump. All...
  3. crutschow

    USB power cable with 35 second delay

    One like this, might be adapted to work for you (to get more than 24s, you would need to increase the timing capacitor value).
  4. crutschow

    Design an analog computer circuit

    Since this is homework, you will need to show us your best attempt at doing the work before we can help. It sounds like you have no idea on what to do. Was this not discussed in the course your are taking?
  5. crutschow

    WallWart conversion...

    Only if it's being powered by the correct voltage. Otherwise all bets are off.
  6. crutschow

    WallWart conversion...

    No matter how you drop the voltage (unless you use a buck regulator) there will be the same amount of power (which generates heat) that has to be dissipated, whether it's in a linear regulator, resistors or diodes. In this case three series diodes is the easiest solution. Use diodes rated for at...
  7. crutschow

    [Solved] Trying to drive a MOSFET with a potentiometer leads to dead short

    I know of no discrete MOSFET that has that characteristic without a substrate diode requiring a connection (normally to the source). There may be some (I know of none) that add an external connection for the substrate diode but it must be biased with an appropriate voltage to keep it from ever...
  8. crutschow

    DC voltage reduction circuit needed

    What's the maximum current at 20Vdc?
  9. crutschow

    [Solved] Trying to drive a MOSFET with a potentiometer leads to dead short

    It is for a P-MOSFET.
  10. crutschow

    [Solved] Trying to drive a MOSFET with a potentiometer leads to dead short

    You are. As danadak noted, the MOSFET is connected backwards. Note the direction of the parasitic substrate diode between source and drain that all MOSFETs have. It's forward biased in you diagram, so provides the near dead short you noted.
  11. crutschow

    LR circuit for PWM Input

    The mechanical analogy of inductance is inertia. The inductance tries to keep the current flowing in the same direction until the inductive stored energy is dissipated. That can cause the voltage across the inductor to reverse, but that just serves to slow down the current, not reverse it.
  12. crutschow

    LR circuit for PWM Input

    You have a common misconception about ground. Ground/common is just the usual name for a node in the circuit that is used as a 0V reference point for all the other circuit voltages (since all voltages are referenced between two nodes). It has no other special characteristic. Obviously no current...
  13. crutschow

    LR circuit for PWM Input

    And my question is, why do you think it would reverse? What do you understand about inductance and how inductors behave, that would lead you to think the current would reverse in your circuit? It would need a voltage source in the reverse direction to reverse the current. That can occur in an...
  14. crutschow

    D Cell Rechargeable pack?

    There are NiMh D-cells available from several different suppliers on Amazon.
  15. crutschow

    Help request: Project measuring the absorbed current

    This is a nit, but you can't "absorb" current, it just flows through the device.
  16. crutschow

    D Cell Rechargeable pack?

    Deleted
  17. crutschow

    D Cell Rechargeable pack?

    That can overcharge the batteries, with possible battery overheating and damage, if the charging is not closely monitored. Better to have a charging circuit that monitors the charging and reduces the charge current when the battery is fully charged.
  18. crutschow

    What incandescent lamp wattage to buy for PSU troubleshooting ?

    Assuming the PSU takes 200W, then its normal operating current is about 200W/240V = .83A, so the bulb would have to be quite large to carry that amount of current without significant voltage drop (likely at least 500W of incandescent bulbs).
  19. crutschow

    D Cell Rechargeable pack?

    Since 4 D-cells require about 6V for charging, you would need to have a boost converter to charge them from a standard 5V USB source. You also would need a charge controller to stop the charge when the battery is full. I doubt you will find a kit for that. It likely would be much easier to use...
  20. crutschow

    What incandescent lamp wattage to buy for PSU troubleshooting ?

    So you want to put this lamp in series with the input power connection?
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