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  1. (*steve*)

    Ic=C x dv/dt

    How your maths? 50Hz means 50 cycles per second. Sin is a trig functions, and you have a multiplier to give a peak magnitude of V. Can you create the equation describing the waveform in terms of t? Having V in terms of t, can you derive dV/dt?
  2. (*steve*)

    Light therapy device

    Is this person qualified? Or just some random person on YouTube?
  3. (*steve*)

    Light therapy device

    At what distance? Over what area? Is it the flood or spot mode? It claims to be a 72W device, but if those are 1W LEDs, there's only 24 of them. There is insufficient information to confirm the claims or to know how it was used.
  4. (*steve*)

    Light therapy device

    The front of the LEDs will not transmit the heat generated on the site effectively, if it did, the risk of burns would be real. I wouldn't place this in contact with your skin. Leave a space of about a half inch to allow the beams from all of the LEDs to spread out.
  5. (*steve*)

    Greetings and salutations

    Hi Jeremy. As well as the other of thing I'm useful with, I've been using python commercially for the past 18 months. I might be able to answer the odd question. Oh and C++ before that. Welcome to Electronics Point!
  6. (*steve*)

    Light therapy device

    Aluminium core board may be hard to get. You may have to find a company that can produce the board for you. This board will probably also need to be mounted on a heatsink. It may also be possible to mount the transistors needing heatsinking to the board and rely on the same heatsink to cool...
  7. (*steve*)

    Light therapy device

    Any of those three transistors could be used in place of the BC547. R2 is calculated as 0.65/I, so for 100mA, the closest available resistor is likely to be 6.8Ω Give me a link to the on line catalog of where you purchase your parts and I'll pick a transistor for you suitable as the pass element.
  8. (*steve*)

    Plotter Cutter Help

    I would remove the double diode and check it out of circuit.
  9. (*steve*)

    High Current DC Switching

    There is something badly wrong if cars and trucks can use starter solenoids for years without them failing, yet the starter on your very small motor fails. Nevertheless, can you measure the resistance of your starter motor. Note that you will need a 4 wire resistance device or possibly pass a...
  10. (*steve*)

    Does 12A and 30A difference matter?

    SimonK Electronic Speed Controller - An electronic speed controller with firmware designed by Simon Kirby. Thicker wire will not do any harm unless it adds too much weight or it is difficult to connect to either the controller or the motor.
  11. (*steve*)

    MOS Power transistors and heat dissipation questions

    From reading the explanation, I thought that the power was being applied externally and the mosfet was in a device which switched it on or off. Whilst switching transients may be an issue, my first concern was that the Vgs was being supplied from an external source and was sufficient to turn...
  12. (*steve*)

    MOS Power transistors and heat dissipation questions

    Carefully measure the voltage between the gate and source terminals of the MOSFET under both conditions and let us know what they are.
  13. (*steve*)

    I Want To Fix My Trimmer

    The charger is almost certainly going to be unable to power the device. I'm sure it takes many times longer to charge the battery than it takes to run it flat.
  14. (*steve*)

    Identify a trimmer

    Seeing it in close-up now, I see what you mean. It is likely a custom part or one made in very small quantities and not stocked by places like digikey. If it is available, you might have to purchase a minimum quantity (which might be a huge number) The manufacturers name is clearly visible, I...
  15. (*steve*)

    Input on a DIY build

    Tell us what the sensor is, and we might be able to figure out how to simulate it. But I'm not sure you actually want to simulate a sensor. Maybe you actually want to do something with the output of a sensor? If the post of your description that states you want to identify three voltage...
  16. (*steve*)

    Any French speakers here?

    Hey, it sounds like something made in the EU. Don't try have to provide documentation in 26 languages or something? I'm only partially joking. I know that at a place I worked at for several years that a medical device we made had to have it's manual translated at great expense into a...
  17. (*steve*)

    Identify a trimmer

    It will be linear, and the hole is "x" shaped. Unless something mates with this trimpot, the shape of the hole is insignificant as long as you have a screwdriver with which to make the adjustment.
  18. (*steve*)

    Questions resect plastic of electronics

    Ok, obviously we are caught in a temporal loop.
  19. (*steve*)

    Questions resect plastic of electronics

    No.
  20. (*steve*)

    High Current DC Switching

    But for high current switching the MOSFETs will probably linger in the saturation region long enough to cause some serious problems. Given that it's only turned on and (presumably) off once, you can get away with much slower switching, but you wouldn't want to have any contact bounce! Of...
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