Search results

  1. audioguru2

    hello guys a lil bit help with variable power supply

    IC voltage regulators work very well and are inexpensive. You could copy their current-limiting circuit. The 0V to 30V power supply in our projects section uses opamps to make current regulation.
  2. audioguru2

    Handmade Power Inventer

    Hi Dr. Dre1, It is good that you made a mechanical pulse-maker then the voltage of the pulses are stepped up with a transformer. You could also use a 555 IC as an oscillator to drive the transformer without using any mechanics. A little 9V battery does not have much power, its max continuous...
  3. audioguru2

    white led

    Hi Pier, Try this regulated current circuit:
  4. audioguru2

    0-30 Vdc Stabilized Power Supply

    Hi Kevin, U3 has an open-loop voltage gain of about 200,000. It has plenty of negative feedback from the current in R7 for it to be linear and reduce the voltage to the input of the output section to be less than 11.2V. The output section has a voltage gain of nearly 3.1. U3 doesn't switch, it...
  5. audioguru2

    white led

    The LEDs don't need a voltage regulator, they need a current regulator. if you can find a high voltage darlington power transistor then I will go to Google and get a schematic for you.
  6. audioguru2

    SN84LS123

    www.datasheetarchive.com also has never heard of a SN84LS123. Texas Instruments website does not have any information on the SN84LS123 and also not for a SN84LS04.
  7. audioguru2

    could any one explaine to me

    A piezo transducer is a ceramic disc with a thin metal layer on each side. It bends when electricity is placed across it. If an ultrasonic signal with a frequency close to its resonant frequency is placed across it then it vibrates strongly. Look in Google for Piezo Theory. 
  8. audioguru2

    white led

    The 200mV reference is a low current voltage regulator with an output voltage of 200mv and it is connected to the input of the reference opamp. Two resistors can allow the opamp to have voltage gain then the amplified voltage can be any regulated voltage within the supply voltage of the IC...
  9. audioguru2

    could any one explaine to me

    An ultrasonic transducer is usually piezo.
  10. audioguru2

    Driving 740 LEDs with variable intensity

    The white LEDs are about 3.5V each. With a 24V supply then 6 can be in series with a 120 ohms resistor to limit their current to 25mA. 740/6= 123.3 strings will make 740 LEDs. 123.3 strings with 25mA= 3.1A max.
  11. audioguru2

    trasformerless powersupply

  12. audioguru2

    circiut help reqest

    Hi Steven, I don't see how the 25k pot can burn out. If something in the circuit is wrong and causes the output to be 9VDC instead of 0VDC then the pot will dissipate only (9 x 9)/25k= 3mW. Its max allowed is probably 500mW.
  13. audioguru2

    white led

    An LM10 has a voltage reference and an opamp in a 8-pins IC. The opamp is set to turn off when its inverting input is higher than the reference voltage, then it turns off the transistor. Resistors are in series to double their voltage rating. A voltage divider is used to reduce the DC sense...
  14. audioguru2

    circiut help reqest

    Nice try, John. Your batteries are backwards.
  15. audioguru2

    circiut help reqest

    No Steven, Look at the pins on the TL082 that Hotwaterwizard attached. It shows a dual opamp. A dual opamp has two opamps in it. Pin 7 is the output of the second opamp. You have it connected to the positive battery by mistake. Pin 1 is the output of the first opamp. You don't have it...
  16. audioguru2

    circiut help reqest

    I said that a ceramic disc capacitor might be microphonic in the circuit with such a high gain. A mylar or metalized poly capacitor (don't you have a "green cap" of 102 to 472 value?) is what should be used.
  17. audioguru2

    what resistor?????

    A 3.3 ohm resistor would reduce the voltage 5.7V. It would get very hot with a dissipation of 10W. Use a 15W resistor and insulate its wires well because it is a shock hazzard.
  18. audioguru2

    what resistor?????

    Its power is 200VA so if the voltage is 115V then its current is 200/115= 1.74A but is it continuous? You can't calculate a resistpr unless it is continuous. Int 4min./8min. means intermittent duty cycle of 4 minutes on then 8 minutes off to let it cool. What is it? What does it do?
  19. audioguru2

    SN84LS123

    There is no part with the number SN84LS123. As I showed you in the Texas Instruments datasheet it is a SN74LS123 or a SN54LS123.
  20. audioguru2

    SN84LS123

    www.datasheetarchive.com has no record of a SN84LS123. In my last reply I attached the datasheet of the SN74LS123 made by Texas Instruments.
Top