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  1. Martaine2005

    Audio amp modification

    If they have the ‘standard’ two wires?. If they are high up in a building, how do you know that they are not 100V line PA speakers?. And, how do you know that they have internal crossovers if you can’t access them?. Also, if you parallel the outputs, you’ll be sending high and low frequencies to...
  2. Martaine2005

    UART half-duplex WeAct STM32F411 - working only when ST Link V2 is connected

    There must be something 'common’ when the ST is in circuit. Maybe a GND or other connection that is required?. Can you post your schematic here?
  3. Martaine2005

    UART half-duplex WeAct STM32F411 - working only when ST Link V2 is connected

    Hi, I know nothing about programming. But if it works when the ST link is connected, surely the code/program has not been uploaded to the microcontroller?.
  4. Martaine2005

    So what's the difference between 12v at 1a and 1v at 12a?

    But current can’t exist without Voltage :cool:
  5. Martaine2005

    So what's the difference between 12v at 1a and 1v at 12a?

    Well, if only Godzilla existed to get a real answer!. And HUGE automobile alternators don’t exist either with 30 million Amps.
  6. Martaine2005

    So what's the difference between 12v at 1a and 1v at 12a?

    I have no idea as Godzilla doesn’t exist. What’s higher up?. Lightning!
  7. Martaine2005

    So what's the difference between 12v at 1a and 1v at 12a?

    Yes, plenty more Volts and plenty more Amps. Thousands, and Godzilla would be crispy and smoking for a while:) The range of applications is huge. It depends on the design and demand the device requires. Underground trains for example, 700V and thousands of Amps. A bedside radio/alarm, 9V and...
  8. Martaine2005

    So what's the difference between 12v at 1a and 1v at 12a?

    An example of big Volts and little Amps (mA). An electric fence. It still certainly makes you jump but won’t kill you. Unless you have medical issues.
  9. Martaine2005

    Basic Volts vs watts question

    That’s if you live long enough!. And I’m being nice!. Only play with low voltage. 12V is just fine. But you CANNOT connect 12V devices to 120V without the required step down transformer. Stop it, just stop it!. Please read all our comments and learn from them. Do some extra research so that you...
  10. Martaine2005

    Basic Volts vs watts question

    Difference of about 42A! Please read up on Ohms law.
  11. Martaine2005

    Basic Volts vs watts question

    The device doesn’t care!. It’s been designed for a particular voltage and current rating. If the voltage is too high, it will damage the device. If the current is too low, the device may not operate properly or at all. Always use the correct voltage and power supply for your devices.
  12. Martaine2005

    Basic Volts vs watts question

    No, No, No! Your device requires 12V DC. You need a 110V to 12V step down transformer rated for 20A.
  13. Martaine2005

    Basic Volts vs watts question

    The current it has to handle. Meaning the copper inner not including the insulation.
  14. Martaine2005

    Basic Volts vs watts question

    I’m thinking….”spliced to a wall plug” means a walwart or plug pack transformer. In which case, as long as it meets the requirements, should be fine.
  15. Martaine2005

    Motor is too fast

    BrushLess Direct Current motor.
  16. Martaine2005

    Power PC speakers from Car Battery

    Yes you can. It’ll consume 3.33333A. So depending on the Ah of the battery, you can have quite a long use. Don’t let the battery get below 10V before recharging.
  17. Martaine2005

    What tool do I need?

    There are heating elements in the handle but the circuitry and fan are in the main units box. The cheaper units have the element, fan and circuitry in the handheld unit. The circuit either fails or the fan fails causing overheating and fire. Not all of course, but it has been a problem with...
  18. Martaine2005

    What tool do I need?

    No, not a large hot air gun. Soldering/desoldering stations have a small pen type heat gun. Its small nozzles help direct the heat. Perfect for SMD work and preheating large ground planes. Do a WWW search for soldering station. Most cheap stations have a heating element and fan in the handheld...
  19. Martaine2005

    What tool do I need?

    Try a decent temperature controlled soldering station. It should have hot air too. But it all depends on what you’re soldering. If you’re soldering copper pipes, then a flame is best.
  20. Martaine2005

    Charging Li Ion batteries.

    Have a watch of EEVblog from many years ago. Lithium ion/polymer charging tutorial
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