Recent content by ScienceGeyser

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    Can Standard Alligator Clips Affect EMG Signal Quality?

    Most EMG lead sets are not shielded. If you have problems with ambient noise, the most common solution is to twist the wires for as far as possible. Twisting improves the common mode noise rejection that is inherent in the analog front end of most biosignal instruments.
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    How Does Differential GPS Handle Timing and Satellite Malfunctions?

    DGPS Systems The DGPS reference station doesn't need to have an accurate clock since it can derive it's time from the GPS data stream. The clock data don't need to be part of the differential offset data. It simply uses the the standard GPS methods to calculate it's position and then compares...
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    How Does Differential GPS Handle Timing and Satellite Malfunctions?

    DGPS Systems Most DGPS systems use a reference station with a known location to calculate offset error resulting from a number of sources. This offset error should be the same for a certain distance around the reference station (roughly 200 miles). The reference station transmits the error over...
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    Can Standard Alligator Clips Affect EMG Signal Quality?

    Contact Resistance Alligator clips should work just fine. The only issue is contact resistance. With any connector, the spring constant of the contact mechanism, the surface resistance of the mating metals, and the contact area are what determine contact resistance. If you use strong alligator...
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    Capacitance & Inductance in Diff. Dielectric Mediums

    Try this site http://www.standard-wire.com/cable_design_equations.html or look in General Cable's electronics catalog. They have equations and characteristics of materials for different wire configurations toward the back.
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    Hi how to make USB host controller

    You should check out FTDI's site and in particular the V2DIP series. You should also check out the info at usb.org.
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    Machine Design - How To Determine Motor HP Etc.

    The typical AC motor like what is in a pump or compressor will not work well for variable speed/load applications. Adding a clutch/brake will mostly just add efficiency losses and not achieve variable speed control either. Having a gear box will allow you to trade some speed for torque and 20:1...
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    Compatibility of Selected UPS Device to Handle Inductive Loads

    Most inverters have a peak rating and a continuous rating. The peak rating usually 50-100% more than the continuous rating. If your inverter is rated @ 1050W continuous then you should have no problem. I'm not sure that you really need to have a sine inverter for this application. There is...
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    Simple diode test doesn't jive. What gives?

    I am not a fan of isolation transformers. In most modern UL listed electronic devices, the Earth ground is not allowed to be part of a current carrying circuit and is simply there for the protection of the user. In the US, the neutral side of the line is bonded to ground at the service...
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    Simple diode test doesn't jive. What gives?

    You are correct about the input impedance on the scope. It needs to operate as a voltage measurement device and high impedance is required to make measurements without changing the characteristics of the circuit under test. Output impedance is essentially the ability of a circuit to drive...
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    Can you help identify home-made potentiometer components?

    Oops! The gold and silver are reversed. Gold is 5% and Silver is 10%.
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    Can you help identify home-made potentiometer components?

    It does look like an oscillator driving a transistor that drives a current spike through the loop to simulate a spark plug wire. The components that are identifiable from the pics are only the resistors and the IC. The resistors from the top are, I think, 560K, 1K, and 100K. If I'm seeing the...
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    Simple diode test doesn't jive. What gives?

    A standard signal generator should have the ability to drive a 50 ohm load without drawing too much current. When connected to a higher impedance load, like an oscilloscope, the output will simply supply less current to the load. The output of the signal generator is a voltage source. If you...
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    Simple diode test doesn't jive. What gives?

    You will have to connect the diode in a circuit to get it to behave as expected. You will also need to connect your scope's reference terminal to the circuit to see the expected wave form. The diode will behave like a capacitor if one side it driven by a voltage source and the other is...
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    Calculating torque required to drive crank and slider

    Great! Mead makes some stuff you might be interested in. http://www.mead-usa.com/ Good luck with your project. Would you mind posting pictures when you are done? I'm sure it will be interesting.
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