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  1. Hero999

    12V battery charger circuit design help

    The first circuit seems to be the best one. Ideally the battery should be charged at a constant current until the voltage reaches 14.5V, then the current is stopped until the voltage falls to 13.8V at which point the charger can be switched to float mode which just regulates the voltage at...
  2. Hero999

    12V battery charger circuit design help

    No, this is the correct forum. You've not received any replies because you've asked a question then posted a link containing the answer.
  3. Hero999

    Need Help For Transistor BU2527AF

    Good for you for trying to repair an old CRT. Most people don't bother nowadays and use the opportunity to buy a brand new TFT flat screen monitor. Yes, you need higher voltage and current ratings and the frequency should ideally be higher too, although you should pay more attention to the...
  4. Hero999

    Newbie doubt regarding battery voltage

    It sounds like the battery is flat so is unable to keep the voltage near 9V when a load is connected. The impedance of the battery rises as it discharges until it's so high, the voltage across the load is too low for it to work.
  5. Hero999

    [SOLVED] Looking for Transistor 2SD2166R or Replacement

    The 2SD2098 is available from Farnel, stock number: 1680155 http://uk.farnell.com/rohm/2sd2098t100r/transistor/dp/1680155?Ntt=2SD2098
  6. Hero999

    led display digital voltmeter

    The schematic is on the datasheet which can be found using Google. http://www.lmgtfy.com/?q=icL7107
  7. Hero999

    [SOLVED] Looking for Transistor 2SD2166R or Replacement

    It depends on where you live and the suppliers in your area.
  8. Hero999

    HELP NEEDED WITH FUSE RATINGS FOR ATX PSU MOD TO LAB PSU

    It looks like you've made your choice but don't worry if you do change your mind later, it should be easy to undo the screws and reconnect the wires.
  9. Hero999

    HELP NEEDED WITH FUSE RATINGS FOR ATX PSU MOD TO LAB PSU

    Yes, that will work, you can also use the LM337 to get a negative 1.25V to 10V. Here's a schematic to illustrate the point I made earlier. If the -12V pin is connected to 0V there will be a short circuit. An oscilloscope's metal case will be connected to the 0V pin.
  10. Hero999

    Driving a Relay using Microcontroller

    That would work but it's probably more expensive and would be more sensitive to high voltage/current spikes. On the plus side, the contact life would be longer, it can switch faster and it's easeir to drive from the MCU. Take your pick.
  11. Hero999

    Driving a Relay using Microcontroller

    It's pretty easy: use a transistor to drive the relay. There are 100s of examples on the Internet. You should learn how to use Google. http://www.google.co.uk/search?client=opera&rls=en&q=microcontroller+relay&sourceid=opera&ie=utf-8&oe=utf-8&channel=suggest...
  12. Hero999

    Where can I get electronic components in Sarajevo, Bosnia

    It's generally very hard to find high-street shops which sell components these days, in any country and the small number of places that do are normally very expensive. The best solution is to go online. RS Components, Farnell and Digikey are the three largest international component...
  13. Hero999

    1 Simple question about led drivers

    I think he's talking about using the LM317 as a constant current source, in which case several LM317 current sources can be safely connected together than the currents will add together.
  14. Hero999

    HELP NEEDED WITH FUSE RATINGS FOR ATX PSU MOD TO LAB PSU

    To measure the voltage between the ground terminal and protective earth, you should connect the meter between the ground terminal and the PSU's case or the ground/earth pin on the plug and make sure there's good continuity between the meter and the If the PC PSU's 0V terminal is connected to...
  15. Hero999

    HELP NEEDED WITH FUSE RATINGS FOR ATX PSU MOD TO LAB PSU

    You shouldn't need any fuses as long as the cable and terminal posts are rated to carry the full current. The PC PSU will be internally protected so short circuits shouldn't be a problem. I have three main concerns: 1) The power supply may need a minimum load current to give the correct output...
  16. Hero999

    Solenoids

    What does blowby mean? At DC, the current through a coil is determined by the series resistance not the inductance. Whether the coil is damaged or not depends on the power dissipation (P = I2R) and its ability to dissipate heat.
  17. Hero999

    NPC Inverter Boost IGBT Zener Clamp

    I have read the datasheet. It's not a complete working inverter. It needs other components to make it work. You can't just wire it up and expect it to work. We need the complete circuit to help.
  18. Hero999

    Power supply is acting like a short but has high resistance

    You forgot to post a schematic so there's no way any one can help.
  19. Hero999

    Putting a light in my closet

    Yes, follow the regulations which is different, depending on you location. Here in the UK you'll need a fused spur which is just a little box with a fuse inside it and is replaceable without switching off the main breaker. The cable run to the spur from the has to be the same size as the cable...
  20. Hero999

    Solenoids

    The capacitance should be as low as possible because it slows it down and can cause resonance. Saturation is the point at which the iron core becomes saturated so an increase in current results in less of an increase in field. When core saturation occurs, the inductance drops to the point where...
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