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  1. BobK

    Automatic Switchover from Car Speakers to Headphones

    You can wire the headphones to speaker outputs with a suitable resistor in series. A 100Ω would be a good starting point. Try it with the volume turned down then turn it up slowly. If it gets to where it is distorting, up the resistor. If it doesn't go loud enough, lower the resistor. Bob
  2. BobK

    Bidirectional Current Source

    Great! Bob
  3. BobK

    Bidirectional Current Source

    Is R3 supposed to be the load? What it is connected to? You show a connection to pin 5 of the opamp, what is that? I would think it should be connected to ground. Bob
  4. BobK

    Power bank idea

    I believe power banks can be bought without the 18650's. Bob
  5. BobK

    How to get your product manufactured.

    How many units are you talking about? Custom manufacturing is not cost effective until you meet some large quantity. I suspect you would need to make at least 1000's before you could do it cheaper than a Rasp Pi. But I am no expert on this. Bob
  6. BobK

    Micro wind turbine

    You need more than that. Please read the resource Steve referred to: https://www.electronicspoint.com/resources/got-a-question-about-driving-leds.5/ Bob
  7. BobK

    how do i drop voltage of a power supply

    And, no matter how you do it, you will need a heat sink since there is 20W to dissapate. Bob
  8. BobK

    ONE CHANNEL REMOTE TO BELL WHICH PULSES WANT IT TO RING

    Okay, the default mode, if you do not modify the board is what you want. The bell rings as long as the button is pressed. And the diagram you posted is the correct way to wire it, assuming the board and the bell are both powered by the same 12V supply. The bell replaces the light bulb in...
  9. BobK

    20 ohms

    Also, for a motor, the resistance will not indicate to the current used when the motor is running. Bob
  10. BobK

    Complete IDIOT to electronics

    Because at 16V they will require much less current, and put out much less light. Bob
  11. BobK

    ONE CHANNEL REMOTE TO BELL WHICH PULSES WANT IT TO RING

    Well, that one has 3 modes as I suggested in my first post. One of them does what you want. But then, you said yours is similar. Can you not link to the exact one you bought? And, posting a link does not help us tell if you have wired it correctly. Edit: Oh, and your wiring is almost...
  12. BobK

    90 degree turn servo and controls

    Hi and welcome to the forum! A servo requires a specific repeating signal to hold at any given position. Servos are not not programmed. You could program a microcontroller to do what you want, or a fairly simple circuit with 2 555 timers to do what you are asking. I have no idea what you...
  13. BobK

    Digital calendar which flashes a LED when out of date range

    You don't have to replace the Arduino with a PIC, you can get the AVR chip itself and run the same program on it that you developed on the Arduino. Bob
  14. BobK

    How are Power Banks and AC Adapters different?

    Yes. The cell phone expects a 5V supply, and it regulates the current at which the battery is charged, through several stages, as you say. And a power bank just does the same thing as an AC based charger, it provides a constant 5V. Bob
  15. BobK

    ONE CHANNEL REMOTE TO BELL WHICH PULSES WANT IT TO RING

    Link to the remote you are using? These often have different modes, which might include on as long as the button is pressed. Bob
  16. BobK

    How are Power Banks and AC Adapters different?

    AC adapters do not have a constant output. The can supply up to the rated current at the rated voltage. The actual current drawn is whatever the load needs. They attempt to keep the voltage constant. A power bank basically does the same thing. They use a 3.7V battery (typically) and a boost...
  17. BobK

    Need fuse

    He means close to (but not over) 1A. Bob
  18. BobK

    Run a wifi station and IP camera off of landscape lighting power?

    Brilliant! It become a 12 to 24V autotransformer. Bob
  19. BobK

    Run a wifi station and IP camera off of landscape lighting power?

    It is not complicated, all you need is a transformer with a 2:1 ratio. Not sure where you would get one though. Bob
  20. BobK

    Problem With Bicycle Generator that Charges My Phone

    Hi, welcome to Electronicspoint. f the generator is indeed putting out > 6V you should get some charging of the batteries. Perhaps you expectation of how long it will take is just off a bit. Do you have access to a multimeter? If so, use it to measure the current when the batteries should be...
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