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  1. (*steve*)

    Another one Tek 2235 power supply problem

    Show us a photo and tell us what is written on them.
  2. (*steve*)

    Remote switch for games console - does it exist?

    Do they turn on if you just apply power? Or do you also need to press a "start" button or similar?
  3. (*steve*)

    How to limit solar current input for testing

    OK, but Rs must be 5 ohms (use 5.6 ohms) to limit the current to around 250mA. You want to run this circuit from an input voltage that is about 2.5V higher than your output voltage under no-load conditions. Do not run it from an input voltage above 30V. For one thing it will be inefficient...
  4. (*steve*)

    Low Voltage Cut Off For Grid Charger

    I did the next step numerically by calculating the power in the MOSFET as a function of the voltage across the bulbs The current through the bulbs is V / (nx + yV), so the power in the MOSFET is (130 - V) * V / (nx + yV) For either bulb, the max power dissipation in the mosfet is when the...
  5. (*steve*)

    Low Voltage Cut Off For Grid Charger

    So the resistance of the 40W bulb can be approximated as 51 + 2.29v ohms (where v is the voltage across the bulb) For the 70W bulb, the equation is 29.5 + 1.3v ohms. We might write this down as R = x +yV, where X is 29.5 and y is 1.3. For n bulbs in series, the resistance would be R = nx + yV...
  6. (*steve*)

    How to limit solar current input for testing

    Draw the circuit you're using and site is a picture of it. It doesn't sound like you've constructed it correctly. For a start you're only mentioning 2 resistors and I see no reason for a 0.2 ohm resistor (1.25/0.25 = 5 ohms)
  7. (*steve*)

    Low Voltage Cut Off For Grid Charger

    I will get back to you soon :)
  8. (*steve*)

    Battery charged by a solar panel?

    The mains adapter will have a voltage which drops slightly under load. This limits the current. This will not happen if your voltage source is stiffer, e.g. a regulated power supply or a battery of sufficient capacity. You could try placing a low value (say, 1 ohm) resistor in series with the...
  9. (*steve*)

    radio waves

    You could say that.
  10. (*steve*)

    radio waves

    You get AC from an oscillator. No moving parts required. Strictly speaking when you say radio I assume you mean radio transmitter, although most receivers contain oscillators too. AC comes from more than steam powered generators.
  11. (*steve*)

    SIMM Memory

    60, 80, and 100 were popular.
  12. (*steve*)

    Need Help for find suitable IC chip

    At the very least we need to see a picture of the IC you need to replace. We need to see it clearly enough that we can read what's written on it. It would also be good to know why you want to replace it and what happened to cause it to fail (I.e. what was the last thing you did?)
  13. (*steve*)

    Using Resistor as Dummy Load

    The teg is a bit like a solar panel in that you need to vary the load in order to extract the highest power. With a fixed resistance load you will get a single data point for each temperature differential. You will not know if the load is allowing you to maximise the power output.
  14. (*steve*)

    Constant voltage load

    It's not a negative resistance, it behaves almost exactly like a zener diode (in both the forward and reverse direction). The main differences are that the knee is very sharp, and the is a "leakage" of about 1mA from memory. But it's true you shouldn't connect it to a power supply. The...
  15. (*steve*)

    Battery charged by a solar panel?

    The version on that page is to similar a lead acid battery. A change in resistor values is required for a different range of voltages. The circuit works almost exactly like a zener diode. In this application, any excess current passes through the mosfet. This loads down the solar panel so it...
  16. (*steve*)

    Battery charged by a solar panel?

    My colleague has a circuit operating from a single lipo cell. It consumes little power and a 6V 50mA solar panel fully recharges the battery in about 5 minutes after running overnight. If your voltage or power need are significantly greater there may be additional requirements (thermal...
  17. (*steve*)

    Led problems

    I'm half a world away. A business class airfare shouldn't cost you too much. You can PM me if you want, but I rarely answer electronics related questions via PM.
  18. (*steve*)

    Led problems

    If you can explain the problem, you may get a solution without needing someone to come out. If you want to pay my expenses though, I'd be happy to come and take a look
  19. (*steve*)

    Low Voltage Cut Off For Grid Charger

    The circuit above will have minimal "bounce back" because it can draw a lower current when the voltage is very close to the cutoff. Sure, a diagram can't hurt. I'm expecting something like 17 and 30 ohms, but there's a wide margin in the estimates :-)
  20. (*steve*)

    Tables of equivalents between russian and western parts

    New Google for "deliver web pages via email", or use the wayback machine, or look for proxies. There are many ways of overcoming these problems.
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