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  1. Alec_t

    My air purifier fans won't turn anymore, making humming noise

    I'd guess a fan shaft bearing has seized. The black thing looks like a drive belt, so if that's not moving but the motor still is, then friction will make the belt hot.
  2. Alec_t

    Coronavirus transmission prevention device.

    I was struggling to see any connection between the corona virus and soda pop, but then I recalled childhood days when Corona brand pop was delivered weekly by a lorry touring the neighbourhood :).
  3. Alec_t

    Doubts battery operation and power of the Chinese plasma pen

    Try it and see.
  4. Alec_t

    Coronavirus transmission prevention device.

    Or how about using a light-weight device which doesn't need globally-warming electricity to power it? A suitably shaped area of microporous fabric worn over the nose and mouth and held in place by elasticated thread. Oh, ...... someone's thought of that already :D.
  5. Alec_t

    Regulator to limit 12v DC current

    That's what I was wondering. Pure water is a very poor conductor. I've just tried two multimeter probes about 1mm apart in ordinary tap water (with goodness knows what dissolved in it) and the resistance between the probes was ~200k. It would be a lot higher in distilled water and require quite...
  6. Alec_t

    DC Power Supply with Adjustable Current & Voltage Limits

    Double-check that the value of R2 is indeed 0.47Ω. With that value the current-limiting shouldn't kick in below about 1A.
  7. Alec_t

    DC Power Supply with Adjustable Current & Voltage Limits

    What is the rating (voltage and current capability) of V1? What is the motor rating? A sensitive LED in series with Q1 collector should give some indication of current limiting occurring.
  8. Alec_t

    DC Power Supply with Adjustable Current & Voltage Limits

    Welcome to EP! BR1 rectifies the V1 voltage and C1 smoothes the result, to form a supply voltage for Q3 and Q4 which are connected as a Darlington pair. D1 (an obsolete type) and R4 establish a base voltage for Q2 which is 2.4V below the said supply voltage. D1, R5 and Q2 form a constant-current...
  9. Alec_t

    Relay question

    Here are some examples of Hall effect latches. The magnetic field needs to reverse to latch/unlatch them (which may or may not be feasible in the OP's setup).
  10. Alec_t

    Relay question

    If you could replace the relay with a switching transistor, that would save space. Have you looked into using a latching Hall effect sensor?
  11. Alec_t

    Questions battery in 0%

    The BMS (battery management system) in your phone probably regards "0%" as the minimum safe discharge level and will switch off the battery to prevent further intentional discharge.
  12. Alec_t

    Galaxy note 10.1 2014 battery problems

    The charging circuitry includes both the external charger and the charging control circuitry which is internal to the Note. From a bit of Googling it appears the Note supports USB-PD, so communicates in some way with the external charger. You say you have checked 'the charger'. Is that just the...
  13. Alec_t

    Galaxy note 10.1 2014 battery problems

    Welcome to EP! Sounds like the charger circuitry has failed. I'm not familiar with the Galaxy Note, but is charger circuitry replacement even an option? If the problem is only with the socket itself you may have a chance.
  14. Alec_t

    Cooktop Igniter

    Google 'piezo igniter'. They're readily available and cheap.
  15. Alec_t

    IR IMAGING DEVICE on the cheap

    Use the IR window from a junk TV etc remote control?
  16. Alec_t

    Questions lithium polymer battery

    From your persistent questions it seems you have failed to understand that none of us knows exactly what is inside your gadget, so can only offer advice/answers based on (a) guesswork or (b) experience of other electronic gadgets. So far you have not acted on the advice you have been given.
  17. Alec_t

    Sky Boxes.

    Aren't those boxes the property of the Sky company?
  18. Alec_t

    Woo-Woo Help please,

    Why would they want to do that? When and why did you let them into your house to install the 'loop'? If they are deaf, how would the loop be useful to them? A metal detector would locate the loop, even if it's embedded in the house walls. Is your house detached from your neighbours' houses? Do...
  19. Alec_t

    Questions lithium polymer battery

    That you stop posting the same request repeatedly. You have already received advice, which you have chosen to ignore.
  20. Alec_t

    Questions lithium polymer battery

    a) Charge it to 2 bars. b) Wait 2 months. c) If the charge state is 0 or1 bars then charge to 2 bars. d) Repeat b and c indefinitely. Report back in 2 years time.
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