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  1. audioguru2

    Simple Parallel Combination Question

    Hi Shaiq, I told you that your 9V supply must be able to provide 540mA to the resulting 16.67 ohms combination of the two resistors. ::) I told you that a little 9V battery cannot supply such a high current, so its voltage would drop. ::) To do this test properly you need a 9V regulated supply...
  2. audioguru2

    555 Based Flyback/Ignition Coil Driver

    The collector of the added transistor should be connected to the positive supply. If you don't use a resistor in series with its base to limit the current then its base will probably blow-up. Additional Options, Browse, select and click "open" the circuit's file on your hard drive then Post...
  3. audioguru2

    Keys finder circuit

    Horray! ;D
  4. audioguru2

    opamp won't output zero

    Hi Kevin, Where's your opamp circuit? Post it so we can see if you are overloading its output emitter-followers with your output resistor. Your output resistor certainly isn't a collector resistor. Transistor circuits and opamp circuits operate completely differently. The collector of an NPN...
  5. audioguru2

    Limitation of current !!

    You are welcome, Mukhalled. ;D I think I know what is your problem. I have seen cars with naked speakers sitting on the back shelf, with no bass and no enclosures! They have the bass cranked up to max to try and make the speakers sound less tinny. Speakers must have an enclosure to keep the...
  6. audioguru2

    0-30 Vdc Stabilized Power Supply

    Hi Zeppelin, The original circuit supplies up to 41V (with no load) to its opamps that have an absolute max supply voltage of 36V. If you use cheap opamps with a 44V supply rating like the MC34071 or TLE2141 then they will be happy. Then the project might be able to supply 2.5A at up to about...
  7. audioguru2

    A timer question

    Hi Heathtech, Your circuit will work if the trigger inputs have a duration that is less than the timing period. The OR gate followed by an inverter can be replaced by a NOR gate. ;D
  8. audioguru2

    opamp won't output zero

    Hi Gsmaster, Most opamps have a max input offset voltage of only 10mV. With Kevin's opamp configured for a DC gain of only 100, its output certainly won't hit the rail. Kevin says that he didn't use the standard gain setting resistors so I am guessing that his circuit has an offset current...
  9. audioguru2

    Limitation of current !!

    Hi Mukhalled, Back in February you had high distortion with this project when you turned the bass and volume too high. When the bass is turned up then the amp must produce 16 times more power. The TDA1554Q amp IC in our project's circuit provides about 5W per channel just below clipping into an...
  10. audioguru2

    opamp won't output zero

    Why not post your circuit so we can see what went wrong? Then we can recommend a solution for you. ;D
  11. audioguru2

    0-30 Vdc Stabilized Power Supply

    Hi Zeppelin, Common opamps are designed for a 30V supply, 36V absolute max. I posted some with 44V absolute max. If you want this project to produce a well-regulated 30V at full load then its positive supply will be more than 38V at full load and about 44V without a load and when the...
  12. audioguru2

    120 VAC

    The utility's mechanical generators produce a sine-wave so would you pay extra (double or triple?) for it to be converted to a triangle wave? A triangle wave has many high frequency harmonics that probably won't pass through power transformers resulting in less voltage. Capacitors are charged...
  13. audioguru2

    0-30 Vdc Stabilized Power Supply

    Hi Maksar, That heatsink extrusion mentioned a length of 87 inches so I thought it is sold that long. I don't know the calculation for a different length than 3 inches, when you double it then the thermal resistance certainly doesn't become half. A thermal resistance of 0.2 would be great with...
  14. audioguru2

    Simple Parallel Combination Question

    Hi Shaiq, If your 9V power supply can supply 540mA (a little 9V battery probably can't, its voltage will drop with such a high current) then it is obvious that both resistors are connected directly to the 9V supply, therefore both have 9V across them. ;D Did you measure any gain from your...
  15. audioguru2

    0-30 Vdc Stabilized Power Supply

    Hi Zeppelin, Most panel meters can't measure their own supply. They need a supply that is completely isolated from what they are measuring. Some people wind a new winding on their transformer (torroid is easy) to power their panel meters. ;D
  16. audioguru2

    Remote Control Land Rover

    Hi Kool, Experienced RF designers have difficulty making stable transmitters and receivers. Usually they must order custom-made parts in quantities of thousands. I don't think you want to follow that route to make only one, soon. High frequency RF is affected by interference and multipath...
  17. audioguru2

    0-30 Vdc Stabilized Power Supply

    Hi Maksar, Those heatsink extrusions are very long pieces that you must cut to length yourself. It is difficult to mount them so that the fins are outside the case but the wiring is inside. I think they are mounted to the inside rear wall of the case with the top and bottom of the case having...
  18. audioguru2

    key chain laser power supply

    Hi Steven, My wifey doesn't like it when I light up her, um you know, with my laser pointer! ;D ;D I'm not dirty enough (yet) to light up other girls. My laser must be getting dirty. It makes a bright red dot with a dirty line through it. The line rotates when I rotate the laser pointer. I...
  19. audioguru2

    0-30 Vdc Stabilized Power Supply

    Hi Ta, Good, you fixed your current jumping problem by replacing the 2N3055 transistors that were destroyed by over-temperature. ;D Since one new one gets much hotter than the other, you can measure the voltage across each one's 0.1 ohm emitter resistor to see how well they match. The low value...
  20. audioguru2

    0-30 Vdc Stabilized Power Supply

    Hi Zeppelin, Welcome to our forum. ;D If you are going to use two 2N3055 transistors and a 30VAC, 4.3A, 130VA stepdown power transformer and high voltage opamps as recommended here, then each transistor will have about 38V across it when the output is at 3A and the voltage is low or shorted...
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