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  1. Alec_t

    A cb radio not working after being sent in for modification

    Out of curiosity, what did Uniden charge you for this CB 'improvement'?
  2. Alec_t

    Senior Project

    Duct tape?
  3. Alec_t

    Applying PWM to load while controlling its current

    As suggested on another forum, you could PWM another FET in parallel with Q2.
  4. Alec_t

    Building a closing switch using household items.

    An interesting challenge, particularly with the timing/frequency limitations! I wonder what 12V battery can put out enough current to meet the '1MA' requirement, and what you can use that isn't available (somewhere) 'off-the-shelf' these days?
  5. Alec_t

    Might I trouble you a moment with my power supply, good sirs?

    Can you post a link to the user manual?
  6. Alec_t

    Might I trouble you a moment with my power supply, good sirs?

    Perhaps your supply was designed as a 'universal' one which needed only one or two component changes to customise it for a specific voltage? If you check the voltage rating of the big electrolytic output capacitors it may indicate what maximum voltage you could expect.
  7. Alec_t

    Senior Project

    The vibration motors are widely available on ebay, as are various wi-fi enabled devices. Reading the specifications of these may give you some ideas for interfacing things.
  8. Alec_t

    Seeking help with 12v dc motor controller on golf buggy

    If you measured 320k the relay coil has gone open-circuit.
  9. Alec_t

    Seeking help with 12v dc motor controller on golf buggy

    Job to tell from the pic in post #6, but the transistor to the left of the relay looks as though it might be fried too.
  10. Alec_t

    Problem with 2.8 -> 5V power supply

    Your circuit may be oscillating uncontrollably. I don't see the 100nF decoupling cap (as recommended in the datasheet), which should be directly across the supply pins of the IC. Does your circuit layout follow the datasheet (section 13) recommendations? Hopefully the circuit isn't on a breadboard!
  11. Alec_t

    Problem with 2.8 -> 5V power supply

    Welcom to EP! Try adding a nominal load, say 1k, and measure again.
  12. Alec_t

    Active high signal

    That should work.
  13. Alec_t

    Volume pot 2 problems really stiff shaft and it worn away

    Welcome to EP! If I understand you correctly it sounds like the pot is beyond repair. Time to replace it.
  14. Alec_t

    Regulating brightness of a high power LED via PWM on a Raspberry Pi

    Welcome to EP! Good question. Your CC source probably already uses PWM to control the current, so additional external PWM might conflict with that. But as Harald suggests, that is unlikey with a reputable LED driver. Hopefully your CC source has some way of setting the current to something a...
  15. Alec_t

    LTspice fatal error: Could not open the WE-CMB.LIB

    Try temporarily removing the transformer or choke and see if you still get the error message.
  16. Alec_t

    LTspice fatal error: Could not open the WE-CMB.LIB

    I've just downloaded and unzipped the WE-CMB zip, giving WE-CMB.lib and WE-CMB.asy, which I put in my sub and sym folders respectively (on the Documents path). Works perfectly. I see from your screenshots that you have your .lib file in a WE-CMB_rev19a folder and not directly in the sub folder...
  17. Alec_t

    LTspice fatal error: Could not open the WE-CMB.LIB

    Welcome to EP! If you are running LTS under Windows10, by default LTS expects to find your .lib model file in your Users/User/Documents/LTspiceXV11/lib/sub folder and the corresponding .asy symbol file in an appropriate section of your Users/User/Documents/LTspiceXV11/lib/sym folder. Unless you...
  18. Alec_t

    laptop motherboard problem !

    Doc, did you notice this thread is ~7 years old?
  19. Alec_t

    How to make a Short Circuit Protection using 8 pin Relay

    An electromechanical relay would likely operate too slowly to protect a transistorized power supply from a short-circuited output, although it could work if the output current became excessive over a relatively long period.
  20. Alec_t

    AC Laptop Adapter -> How to make 19v output into 5v?

    The present output rating is implicitly 90W/19V = 4.7A. It is most unlikely a simple resistor change would safely allow any greater current, because the designed current capacity of any components such as the high-frequency transformer secondary, the output smoothing choke and power diode would...
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