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  1. Alec_t

    One cell power bank troubleshoot

    The most likely point of failure would be the IC, since it has to handle the relatively high (compared to the currents in other components) charging current and the switched current in the boost converter stage. So you'd begin by finding a source for replacement ICs. Unless you're buying...
  2. Alec_t

    110VAC hair clipper on 220VAC help please

    If the clipper is of the mechanical resonance type the frequency is important. 50Hz may not work.
  3. Alec_t

    MFOS VCO fault

    Good to hear it's sorted.
  4. Alec_t

    Latching relay for actuator use?

    Here's a suggested alternative basis for switchng off the relay once the actuator has reached its limit, avoiding the need for a latching relay. It does, however, require a single limit switch external to the actuator to sense when the door is fully open :- This circuit has a photocell plus...
  5. Alec_t

    MFOS VCO fault

    What do you call that waveform; a 'trine' or a 'sinangle'? :D.
  6. Alec_t

    Latching relay for actuator use?

    Is this a chicken coop door opener/closer? There are various threads about that which may have useful info for you.
  7. Alec_t

    MFOS VCO fault

    Did you remember to reconnect pins 1 and 2 after installing the new C13? The waveforms look reasonable shapes (apart from the sine), but static pics of the screen would be far better than videos show to show details of voltage levels, distortions etc.
  8. Alec_t

    Datasheet And Schematics

    I doubt Haier will release that model's data either.
  9. Alec_t

    One cell power bank troubleshoot

    Welcome to EP! I agree with Kellys_eye. The IC will control/provide a converter function to boost the cell's 3.7V to 5V, It, or another IC on the cell itself, will also need to provide controlled, safe charging and discharging of the cell.
  10. Alec_t

    Chokes on DC power supplies?

    A long cable will act as an antenna to pick up interference, so putting the filter at the destination will help to suppress that. You may well need a filter at both ends of the cable.
  11. Alec_t

    Op Amp with a/c output

    Here's an alternative, much simpler circuit which I think stands a better chance of working with your setup. It does, however, require a ground (chassis) connection. Inputs 1 and 2 are where the sensor connects. R4 emulates the sensor coil resistance. D3 prevents Q1 from shorting terminal V to...
  12. Alec_t

    MFOS VCO fault

    Correct. Hope a new C13 does the job.
  13. Alec_t

    LPG Sensor ckt help

    This page has the spec for a module using the MQ135 sensor (which it seems yours has). I'm guessing the pins are Analogue out, Digital out (TTL compatible), Vcc (+5V) and Ground.
  14. Alec_t

    DC-DC converter

    How did you wire it up? Connecting an ammeter directly across (i.e. in parallel with) a power supply will almost certainly destroy the ammeter (and the supply if it isn't current-limited), because the ammeter is almost a short-circuit. You wouldn't be the first person to try to "measure how much...
  15. Alec_t

    Mosfet driver ir2112 circuit high side is not working

    Where's the rest of your circuit? HO won't rise to the correct bootstrapped level unless VS gets pulled up by the upper MOSFET. With the circuit as shown I would expect HO to be pulsed at 12V, not a constant 5V.
  16. Alec_t

    MFOS VCO fault

    I should have said unplug U6 before doing the C13 check.
  17. Alec_t

    DC-DC converter

    Try increasing the load current to, say, 50mA or more and see if the output voltage is closer to the spec.
  18. Alec_t

    Mosfet driver ir2112 circuit high side is not working

    The mistake is that you haven't provided anywhere near enough information. We're not clairvoyant. A schematic would be helpful.
  19. Alec_t

    MFOS VCO fault

    That suggests either (a) there is indeed a short between pins 2 and 3, or (b) C13 is shorted or leaky. Discharge C13 then try an Ohms test on it: the meter should stabilise at a high resistance value.
  20. Alec_t

    DC-DC converter

    Welcome to EP! What load is the converter driving? Regulation might be poor if the load is only a few mA.
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