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  • Users: hmic21
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  1. hmic21

    How can I get an osciallator to work on its 3rd Overtone?

    Hello all, I recently ordered a 40.7125MHz crystal to make an oscillator, but I can't get it to resonate at that frequency. I first tried a simple Colpitts configuration, and it was oscillating at 1/3 the frequency. I then tried a circuit with a cap between the base and the emitter, and a tank...
  2. hmic21

    Colpitts oscillator

    Does anyone know how to simulate a colpitts oscillator on PSpice? I'm modeling the crystal with a cap and an inductor in series and both of them in parrallel with a cap but can't get it to oscillate at all. They told me to kick start it by introducing some noise by adding a VPulse source at the...
  3. hmic21

    Best ESA for Keyless Entry System

    Hello all, I'm currently working on re-designing a keyless entry system for a car to maximize its range. Right now I'm concentrating on the design of the antenna. The current system seems to have a simple brass, top loaded monople. The frequency is 315 MHz and the antenna has to fit in a small...
  4. hmic21

    Need help interpreting stepper motor curve

    Hello all, A recently recieved a curve from a stepper motor manufacturer. It is torque (oz-in) vs. speed (rps). It also has power vs. rps on the same graph, represented by a dotted line. I thought power was torque (N-M) * Velocity(rad/s)? I do these calculations, and the power i calculate is...
  5. hmic21

    Measuring Torque without a dyno

    I was wondering, what is the easiest way to measure torque on a 1hp dc motor? I looked on their web site, and the motor manufacturer didn't have torque vs. speed curves. All they had was something like: Torque(in-lbs): 0 35 70 Current(Amps): 2.35...
  6. hmic21

    [b]Motor efficiency and a dynomometer[/b]

    Hello all, I have been given the task to find the motor that works best as a generator. By best I mean as far as efficiency and output power go at the lowest rpm possible. I have set up a small experiment to test a pm dc motor,a stepper and a dc brushless. I know my experiment has quite...
  7. hmic21

    Motor as generator at low rpm high torque??

    Hello all, I am having trouble finding a motor that can be used to power up a propeller to about 12 rpm then shut off and act as a generator with the propeller being driven by an underwater current. The obvious problem here is though we have a lot of torque, what motor can generate any...

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