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  1. Alec_t

    Nichrome wire heating project. help please!

    No. The heated object will lose heat at a rate determined by its surroundings, so the temperature won't be limited to a fixed value.
  2. Alec_t

    ECU unit

    Apart from the caps, semiconductor devices can become leaky if stressed electrically or thermally.
  3. Alec_t

    Ultrasonic sensor working underwater?

    Welcome to EP! Some ultrasonic sensors are designed to work in liquid, others aren't. High enough sound/ultrasound levels can stun or harm animals. Shape detection would depend on the size of the object relative to the transducer dimensions and operating frequency. Sonar, with a directional...
  4. Alec_t

    ECU unit

    Could be leakage current somewhere it shouldn't be, perhaps causing a cap to charge or discharge over a long period. Contaminants between pcb tracks or between IC pins can provide leakage paths. Electrolytic caps can go leaky with age.
  5. Alec_t

    Nichrome wire heating project. help please!

    To limit the temperature to a set value you will need some electronics to measure the temperature and provide feedback to a transistor/switch which controls current through the nichrome element. Thermal insulation around the heated object will be a major factor in determining how much power is...
  6. Alec_t

    Microphone and camera using same power sounds like crap

    That probably passed so little current that the poor little mic was starved :(.
  7. Alec_t

    Help, Please with hot wire foam cutter

    You can use a resistor-capacitor low-pass filter to smooth the voltage reading.
  8. Alec_t

    Microphone and camera using same power sounds like crap

    Do you have a spec for the mic? Normally an electret mic rated for 1.5V would get its supply via a load resistor from a higher voltage source and that supply would be decoupled by a capacitor.
  9. Alec_t

    Microphone and camera using same power sounds like crap

    Are you using a star ground system? If not, ground currents from the camera and supplies may get superimposed on the microphone signal.
  10. Alec_t

    'Deliberate' lifespan of modem/routers?

    A lot of today's electronic gizmos are squeezed into small housings and components inside can get rather warm. Electrolytic capacitors are the prime candidate for failure and have rated lifetimes typically of just a few thousand hours. Elevated temperatures shorten their actual working life.
  11. Alec_t

    switching the VSS line of an IC

    What IC is it?
  12. Alec_t

    Can you make my 12v LED light up?

    Well, we still don't know the true nature of the PWM signal, but hey, if it does the job that's great. Glad the circuit is now working as intended. Tweaking a few things here and there is par for the course with prototypes. R4 might as well stay at 10k. Am on to the second bottle of that crate...
  13. Alec_t

    Powering a wireless door chime transmitter.

    Sounds like the transmitter is faulty. Can you get a refund? I have a cheapo wireless bell, but the transmitter battery has so far lasted over a year. The receiver/sounder is intended to take 3 alkaline 'C' cells. They last only 3 or 4 months, so I modded the receiver and now run it from a USB...
  14. Alec_t

    Can you make my 12v LED light up?

    I don't know what your PWM voltage and duty-cycle signal characteristics are, but I've been simulating the circuit and I think it will respond better to the PWM signal if we move C1 so that it connects between the right-hand end of R1 and ground, i.e. it will then be connected in parallel with...
  15. Alec_t

    Forum Category Feedback

    I like the fact that the Homework Help now stands out more clearly.
  16. Alec_t

    Can you make my 12v LED light up?

    Same position, but observe correct polarity. Usually a black stripe denotes the negative connection.
  17. Alec_t

    Can you make my 12v LED light up?

    Sounds like the PWM frequency is a lot lower than the 20kHz I assumed. Increasing C1 to 10uF or so (>=25V rated) should cure the flicker. You might be able to salvage a suitable cap from some dead/redundant kit. I'm surprised the PWM frequency alters. Normally it's fixed and the duty cycle...
  18. Alec_t

    VFD causing noise

    The ammeter cannot directly read a PWM'ed current correctly. IMO you need to RC filter the voltage developed across the shunt and apply the filtered signal to the ammeter.
  19. Alec_t

    Water pump question

    Define 'constant pressure'. Mechanical pumps of the diaphragm, peristaltic or piston type would produce distinct periodic pressure pulses. Is that acceptable?
  20. Alec_t

    Can you make my 12v LED light up?

    I'll enjoy a simulated beer. Cheers, Dave!
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