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Member #40615

Member Since: May 30, 2008

Country: United States

  • Power MOSFETs have very low gain – often smaller than one. You need to control them with a higher voltage than the voltage being switched. This is because they’re voltage-controlled devices.

  • Power MOSFETs are only good at handling power because they have such a low resistance that they can carry a lot without warming up much at all. Try to control the same loads linearly and they let out the magic smoke.

    At the very least you will need a beefy enough heatsink and fan to suck away the xx watts of heat it will be generating.

  • That depends entirely on the voltage being controlled. Like any other power MOSFET you need a higher voltage at the gate than the voltage you want to control.

  • Power MOSFETs have really low gain. To control 3.7v, you want the gate voltage to be HIGHER THAN 3.7v.

  • The regulator on these is a surface-mount linear regulator, which theoretically is good all the way up to 21 volts or so, as long as you stay within heat limits. These take very little power, and my project had 18 volts handy, so that’s what they’re getting. It works great.

  • It has a built-in voltage regulator, you will have to jumper past it if you want to run this off of 5 volts or lower. Also be mindful of the pinout. Go by the location of the wires because the color of wires is COMPLETELY inconsistent. (The ones I have don’t just have a different order, they don’t even have all the same colors…)

  • I am only starting to play with these myself, but you may be giving it too large a time slot.

    It’s like a photo film. The capacitance is how sensitive it is – the lower the capacitance, the more sensitive it is. The integration time is the exposure time. So, make it a less sensitive ‘film’ by giving it more capacitance, and give it less exposure by reducing the time slot, and you should get lower values.

  • I discovered, while soldering pins to this board, that the sensor has a bluish optical coating on it that can be damaged if you are careless.

  • The higher the sampling rate, the lower the accuracy, but I expect it’d read gross changes like that pretty well.

  • I’m not sure a filter makes much sense or difference here. Not a lot of point finessing out the fine details of the signal when the data you want is SUPPOSED to be a flat line. It’s a barometer, not a microphone.

    Considering it’s a little chip, not a computer, I doubt it’s anything fancier than sum(n)/n.

    I’ve verified to my satisfaction that the part is as accurate as they claim, anyway. Took thousands of samples and did statistics, and the numbers I got fit the specifications to the nose.

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