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  1. Hero999

    Re: Repairing PS, can't find this part or information... Litton varistor?

    Take a closer look at the filter capacitors: Are any of them swollen? Is there any sign of fluid leaking out of them? Are the terminals corroded? If the answer to all of the above is no, they might all right, although filter capacitors do go bad without showing any physical sings of doing...
  2. Hero999

    Engine Speed Controller

    Why not just increase the speed when the battery voltage drops below a certain level?
  3. Hero999

    Re: Wave Bubble?

    What's a PI? It sounds like you're just being paranoid. The only secret police in the US are the FBI and they have restricted powers. Why don't you emigrate to Russia or China where the secret police can beat you up and make you mysteriously disappear?
  4. Hero999

    Re: Repairing PS, can't find this part or information... Litton varistor?

    It's an NTC (negative temperature coefficient) resistor. When it's cold it has a fairly high resistance, as it heats up its resistance drops. It's used a an inrush current limiter. When the power is first applied it's cold and its high resistance limits the current, as it warms up its...
  5. Hero999

    Re: Wave Bubble?

    Remove the tracker device. Why is the tracker there anyway? You say you're being stalked, report it to the police. Do you live in a country with an authoritarian government? Perhaps you're being spied on by the secret police. Just inspect your car for tracking devices before you drive.
  6. Hero999

    Re: Wave Bubble?

    The same way they can track the tracker. They use a direction finder and field strength meter to get a rough direction and distance between them and you. If anything, the jammer is going to make their life easier not harder as the signal from your car will be stronger.
  7. Hero999

    Re: Ldi/dt of an inductor

    Because that's what inductors do: they try to keep the current constant. Think of a flywheel: difficult to get spinning and hard to stop once spinning. An inductor stores energy in the form of a magnetic field which takes energy to build and releases energy when it collapses. When there's no...
  8. Hero999

    Re: Relay

    What's an SPS relay? Single Pole Single What? Throw, I'd guess? No conversion is necessary, just only use one of the poles or better, connect them in parallel to increase relay life.
  9. Hero999

    Re: power surge kill power supply/motherboard

    The noise is nothing to do with the high voltage protection, it is generated by the high frequency switching transistor in the supply and the mains. Extra filtering will reduce the noise but there's no way to eliminate it completely.
  10. Hero999

    AC Clamp on current meter to measure dc current??

    It's not possible. Cheap AC clamp meters use a current transformer principle which only works on AC currents, for DC you need a hall effect sensor. A DC clamp meter will cost more but  that's life. ;)
  11. Hero999

    Re: need help asa

    Thay may have been breaking the law too. It could have been a pirate station.
  12. Hero999

    Are these 2 caps the same?

    The more expensive one is rated to 100V. The cheaper one is probably rated to 50V but it doesn't say.
  13. Hero999

    Re: coaxial cable and GHz frequency

    What's the point of the 10k resistor? It's in parallel with 1R so it's not going to make any difference. He needs something to trigger the alarm, he could configure the other half of the op-amp as a comparator with a small piezo buzzer connected to the output so it makes a noise when the LNB...
  14. Hero999

    Remote control vibrating alert bracelet

    A wireless doorbell? Is he deaf or is it just that he can't understand you? If he can't hear then you could add a motor with a weight on the shaft to the wireless doorbell to make it vibrate as well as chime.
  15. Hero999

    Re: coaxial cable and GHz frequency

    That won't work, you need to measure the DC current flowing though the co-ax, not just the voltage. You need to break the shield and wire the resistor in series. The break and the resistor need to be as small as possible to avoid ruining the properties of the transmission line. I'd recommend a...
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