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  1. (*steve*)

    Cheap Chinese Laser Cutters

    The increased size of the bed alone is probably worth the price difference. However you need to consider the type and cost of materials you plan to use, and how you're going to source them. If you're planning to use acrylic sheet, then you'll be thinking about buying it by the sheet. A full...
  2. (*steve*)

    Step down transformer reference list?

    230V is close enough. As would 220V or 250V. The output voltage will vary a little too, but that's why they have a regulator :-)
  3. (*steve*)

    How to connect LED strip to batteries

    If you can get 2 hours of continuous runtime, then if you want it running for 24 hours, the duty cycle must be 8% or less. So 3 or 4 seconds per minute would be fine.
  4. (*steve*)

    MOSFET Issues

    Is the mosfet getting hot? Can you read the voltage across the MOSFET while it's on with this load? Likewise can you measure the voltage across the battery? If you're doing that, you might as well measure the voltage across the load as well. In all cases, measure as close to the device as...
  5. (*steve*)

    Cheap Chinese Laser Cutters

    Yeah, that's a much more serious machine. Points to note: It doesn't seem to have automatic Z height. That's not a huge issue if it's used by trained or experienced people though. There is nothing below the honeycomb. Small pieces will drop through. This is just a cleanup issue mostly. A...
  6. (*steve*)

    How to connect LED strip to batteries

    Switches can have different ratings with AC vs DC and higher vs lower voltages. But because this switch don't say so, I'd assume it's not up to the task. If you can't find anything then take a look in a shop selling car accessories. Switches for use in cars are generally rated for higher...
  7. (*steve*)

    How to connect LED strip to batteries

    It looks like it would work. It would give you a runtime of a little more than 2 hours. If you don't want it to run at full brightness all the time, you can get a PWM controller which will allow you to dial up a brightness. At less than full brightness you battery will last longer.
  8. (*steve*)

    How to connect LED strip to batteries

    A lot depends on the power required by the LEDs. The more power they require, the longer you want them to operate, and the brighter you want them to be, the larger the battery needs to be. If we can find out the power requirement for the LEDs, and how long you want them to operate, and how...
  9. (*steve*)

    Converting Double Insulated Light To Faux-Case Grounded

    If you can find a way to add a small fan to blow air over the heatsink, the effectiveness of the heatsink will be greatly enhanced.
  10. (*steve*)

    How to connect LED strip to batteries

    Yeah, they get called 1.5 volt batteries because the nominal voltage is 1.5 volts. Larger batteries (e.g. D vs AA) have the same nominal voltage, but are capable of higher current, or the same current for longer.
  11. (*steve*)

    Conversion of decimal to binary

    I would suggest that you should round off the fractional portion and store the whole number portion as 0111000. 8 bits is enough to store the numbers 0 to 255, or -128 to 127, or 0 to 127.5, or -64 to 63.5. or a whole lot of other options depending on how you decide to represent the number in...
  12. (*steve*)

    Can I test electronic components whithout removing it from the circuit board?

    Sometimes you can adequately test components in circuit, often you cannot. The more you know about the circuit, the more you can judge what the effect will be on your measurements caused by the circuit. If you have a working and a non working unit, you can compare the results, looking for...
  13. (*steve*)

    OP amp guidance for newbie

    Hi Brian, the output of a wheatstone bridge is a differential signal. You should be looking at the difference between the two outputs, probably by connecting them independently to tell different analog input pins. You should not as any additional resistance to ground. I assume the bridge...
  14. (*steve*)

    30W LED amplifier from 12V

    Just as an aside, here are some images of a good high power COB LED module and a bad one. Both are being operated at a low current (around 20mA from memory) Note that one has all the elements illuminated at the same brightness, and the other has randomly lit elements at very different...
  15. (*steve*)

    Cheap Chinese Laser Cutters

    300mm x 200mm is tiny. The small one I use has a 300mm x 500mm bed, and there are plenty of times when it's too small. I would agree that getting to know your local hackerspace's laser cutter would be a great idea. Be aware that CO2 laser tubes require cooling. Our cutters have an external...
  16. (*steve*)

    30W LED amplifier from 12V

    You probably mean 350mA. mAh is a measure typically used as a measure of capacity of batteries. I assume what you want is a LED driver that you can control via PWM from your Arduino. What voltage source do you have available? Do you have a (say) 28V power supply? Do you want to use a...
  17. (*steve*)

    What should I get for beginning electronics?

    Not to mention: A used rubber tyre A long piece of string Three bananas
  18. (*steve*)

    OP amp guidance for newbie

    The input has a high impedance. When you connect your voltage source to it, most of that noise will disappear. If you know the impedance of your voltage source you could initially replace it with a resistor of that value. A simple op amp circuit with a gain of 100 will give you a 0 to 2.5V...
  19. (*steve*)

    What should I get for beginning electronics?

    So, @Nanren888, the fourth rule is that sometimes my three rules are a simplification? Well played :-)
  20. (*steve*)

    Capacitor discharge pulse circuit topology, series capacitor?

    I should add that it's also entirely possible to have the switching element between the capacitor and the inductor, charging the capacitor directly before discharging it through the transformer. Again, this requires that the charge current is less than the holding current for the switching...
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