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  1. Alec_t

    Help regarding breathing sensor

    Welcome to EP! Do you want to measure air quantity or flow rate, or merely detect that breathing occurs?
  2. Alec_t

    Free software and libraries to simulate electrical system?

    Try LTspice. It's a free download from Analog Devices. A lot of members here use it. There's a User Group too.
  3. Alec_t

    DC Motor supply voltage 6v from 3v3

    Welcome to EP! You need a DC-to-DC boost converter with a suitable spec. Loads advertised on the web.
  4. Alec_t

    LTspice, Warning node is floating in XNOR simulation

    Welcome to EP! With any query concerning LTspice, please post your .asc file. Also, note that the default FET models should be replaced by 'real world' FET models to run a useful simulation.
  5. Alec_t

    Noisy CPU fan - reduce its RPM

    If you do there will, of course, be less cooling effect, so your CPU may overheat. The problem may lie with poor thermal coupling between the CPU and its heatsink, so the fan is just doing its best to stop the CPU frying.
  6. Alec_t

    Anode and Cathode

    Welcome to EP! This may help.
  7. Alec_t

    Unbalanced super capacitors in series

    That seems reasonable (I haven't researched the topic) and can be modelled (at least approximately) as a parasitic resistor in parallel with a perfect cap. So if each cap, as modelled, has a parallel resistor then the voltage at the junction of the two caps in series will tend towards the...
  8. Alec_t

    Unbalanced super capacitors in series

    It can result in one cap having virtually all the 4V across it, unless both caps have identical leakage.
  9. Alec_t

    Unbalanced super capacitors in series

    It's most unlikely that the two caps would have exactly the same capacitance, so they won't share the 4V equally even when brand new. It's possible too that they will age differently, increasing the imbalance. As you can't predict their behaviour you have to design around it, assuming a worst...
  10. Alec_t

    New Stompbox Project

    I second AG's suggestion of using a jfet preamp. That will ensure the loading on the guitar pickup will be largely unaffected by tinkering with a subsequent circuit stage.
  11. Alec_t

    New Stompbox Project

    If you are only ever going to be using a single 9V battery as the power supply it would be preferable to use op-amps which have a 'rail-to-rail' common-mode input range (to make input biassing less critical) and a rated single supply voltage range which includes 9V.
  12. Alec_t

    Need Help with simple 9V circuit design.

    Unless the motor is very low power and you aren't concerned that the rpm will drop as load increases, using a potentiometer in series with the motor is a poor way to control the speed.
  13. Alec_t

    tens of years battery life ?

    According to Battery University, alkaline cells have a self-discharge rate of 2-3% per year. Have you taken that into account?
  14. Alec_t

    How to replace thermal transformer fuse

    Take care that heat from the soldering doesn't trip the fuse.
  15. Alec_t

    4116r lf 1-103

    That IC contains a network of 10kΩ resistors. Unless you have an intricate knowledge of the workings of all the MCUs in your car I don't see any way the IC could be used to enhance any aspect of the car's performance. I supect you've been scammed :(. Welcome to EP!
  16. Alec_t

    Automatic chicken door

    Sounds like your project could use a pulse-coded IR transmitter (such as used in TV remotes) one side of the door opening and a matching IR receiver the other side to make a broken-beam detector. The detector would control a relay or electronic switch to cut off the actuator supply for some...
  17. Alec_t

    Piezo buzzer operation

    I'm guessing the micro would output driving pulses to the main piezo terminal and monitor the strength of the signal picked off from the feedback terminal. It would the adjust the driving pulse interval to maximise the signal strength.
  18. Alec_t

    new original voltage doubler circuit

    I cant't tell from your drawing. Are those supposed to be switches in the bottom rail, or is it just a wavy line?
  19. Alec_t

    irf9640 p-chan mosfet switching buck converter blows without load, whats wrong

    Q2 won't switch on reliably. The IRFP250N has a Vgs(thr) which can be as high as 4V. As noted above, this is a linear regulator design, not a switch-mode one. LTspice simulation confirms no oscillation occurs. There is no accurate reference voltage source to establish the output voltage, so the...
  20. Alec_t

    Reversing polarity through signal from mouse switch

    No. a1 = 14, a2 = 24, b2 = 22. The switch gets wired 'diagonally' for reversing; i.e. 12 connects to 24, 14 connects to 22. The 'i' in my diagram is actually a + sign partly hidden. The A1 coil is the 'reset' one to bring the contacts to the state shown in the datasheet. Your chosen relay is a...
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