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  1. Alec_t

    Looking for more help with my electronic ‘bagpipe’ project...

    Try de-tuning the drones circuit slightly. Does that affect the warble frequency? Are you feeding the mixer with the voltages across the timing capacitors of the drone/chanter (~triangle waveforms), or the voltages across the IC outputs (square waveforms)?
  2. Alec_t

    I think I might be dumb.

    I agree. So pins 3 and 4 (not 3 and 2 as per my post #5).
  3. Alec_t

    Step up from 5v Powerbank

    Perhaps the 0.9A rating is for the peak (start-up) current, rather than the normal full-speed running current?
  4. Alec_t

    I think I might be dumb.

    Wow ! That's an expensive indicator light, but will do the job. The 12V rating suggests it already has an internal current-limiting resistor, but I'd recommend connecting an external (~1k) resistor in series with it, at least initially, in case it doesn't, or if it proves too bright. It looks as...
  5. Alec_t

    I think I might be dumb.

    Welcome to maker.pro. That image crops off some of the data. Can you post one which shows more data? Although the transducer pnp outputs are rated for 500mA, an external indicator LED need only draw a few mA.
  6. Alec_t

    Looking for more help with my electronic ‘bagpipe’ project...

    The Vcc notation applies to bipolar transistor circuits and means "the (positive) Voltage at the Collectors". For circuits with field-effect transistors the notation is Vdd, meaning "the (positive) Voltage at the Drains".
  7. Alec_t

    Looking for more help with my electronic ‘bagpipe’ project...

    I'm surprised. The IC needs a DC supply, shown on the datasheet as +Vcc at pin 8. AC will almost certainly kill it. Edit: A wall-wart rectifies the input mains supply, which creates many harmonics of the mains frequency, well into the audio range. Depending on the quality/construction of the...
  8. Alec_t

    Step up from 5v Powerbank

    No. The flow rate would be less, but I doubt it would be halved. The wattage would be less too.
  9. Alec_t

    Step up from 5v Powerbank

    Yes it is. The power to drive a fan varies approximately as the cube of the rotational speed. Reducing fan speed also reduces the fan motor back-emf, so the current increases.
  10. Alec_t

    Drive a 1KW Marine Transducer

    Have you tried Googling for "echo-sounder circuit"? It might be possible to beef up an existing circuit to handle 1kW. Welcome to maker.pro.
  11. Alec_t

    Step up from 5v Powerbank

    Would you have enough air movement if the fan could work at 5V?
  12. Alec_t

    Sunbeam Electric Bedspread stopped heating. Anyone know what the element resistance should be?

    It does increase, but probably not by much, given that an electric blanket doesn't get very hot.
  13. Alec_t

    Voltage amplifier with OPAMP

    That circuit won't get you 11.9V out of a LM324 with only 12V as its supply. You'd need an op-amp with a rail-to-rail output capability, or else use a higher supply voltage.
  14. Alec_t

    Some input/help on this circuit

    Ok. I give in :).
  15. Alec_t

    Some input/help on this circuit

    Agreed, but should suffice for low-current use such as an op-amp supply.
  16. Alec_t

    Some input/help on this circuit

    Provided your 9V AC source does not have one terminal grounded, this arrangement would give you positive and negative supplies :-
  17. Alec_t

    H bridge circuit simulation in LTSpice

    LTspice doesn't know what 'neutral' means. With the two DC supplies in series, the node where they connect can be used as circuit ground if you wish. In that case connect the ground symbol there. The high-side FET (M1 or M4) needs its gate voltage at least 4V higher than its source voltage to...
  18. Alec_t

    H bridge circuit simulation in LTSpice

    Please post you .asc file.
  19. Alec_t

    Looking for more help with my electronic ‘bagpipe’ project...

    Doesn't the iPad have a "save as" option? If not, you need a proper computer :) . For those interested, I'm attaching the MP3 file with the .txt extension added. Delete the .txt extension to play the file.
  20. Alec_t

    Looking for more help with my electronic ‘bagpipe’ project...

    This site doesn't accept uploading of an MP3 file, but if you change the file extension to .txt the file will upload ok and the extension can be changed back again by users.
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