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  1. audioguru2

    Tank ckt

    A tank is an inductor and a capacitor in parallel and they resonate. At the resonant frequency their impedance is very high and current transfers back and forth between the inductor and the capacitor.
  2. audioguru2

    Another INVERTER we can talk about..

    Your schematics show how to connect the ICs together. The 106 pages of the TAS5508B PWM processor shows where the audio inputs connect to. It is a lot more complicated than I thought.
  3. audioguru2

    Not Gate

    Who made-up the silly name "NOT Gate"? Why doesn't everybody call a digital inverter an inverter?
  4. audioguru2

    0-30 Vdc Stabilized Power Supply

    Hi Esil, Welcome to our forum. ;D People have made the original project and report that the max output is only about 25VDC at about 2.5A. I made a list of the circuit's voltage losses to show why. The transformer's voltage rating is too low for the project to have a well regulated output of...
  5. audioguru2

    Need help saturating a transistor for 2 amps

    The darlington barely turns on with a base current of only 1mA. It will "saturate" well with a base current of 1.6A/250= 6.4mA or more. Its max base current is 100mA. Select a resistor for the blinky LED to conduct 30mA: (6.6V-1.3V-2.25V)/30mA= 102 ohms. Use 100 ohms. Select a resistor to turn...
  6. audioguru2

    Inverter Circuit 12V DC to 230VAC Sine Wave

    The output of a comparator IC can't make variable height (voltage) pulses because its output is either high or low. The PWM pulses are converted to a smooth sine-wave with a lowpass filter.
  7. audioguru2

    audioguru fm transmitter

    Of course it does. Look in its datasheet. It is typically 2mA with the 10mA load of the circuit. You can buy lower power voltage regulators if you need them.
  8. audioguru2

    audioguru fm transmitter

    It is inaccurate to calculate LC values for a tank that operates at VHF or above. How much is the stray capacitance across the coil, trimmer capacitor or other parts connected to them? How much is the capacitance inside the transistor? How much is the inductance of each piece of pcb track or...
  9. audioguru2

    Choosing the right equipment wire?

    Hi Zeppelin, Over-rating the size of wires for equipment interconnect is not overkill when it provides a nice low voltage loss. You don't want to set the regulated supply to 5V and have fluctuating 2V to 5V at the equipment, do you? Good regulated supplies for external equipment use "remote...
  10. audioguru2

    6 speakers on 4-channels stereo!!

    Hi Mukhalled, Most car stereos produce 50 Whats for a moment for each of their four channels for a total of 200 Whats. The outputs at such a high level will have very high distortion and since it isn't continuous, I call it Whats. They produce only about 14 Watts continuously for each of their...
  11. audioguru2

    Need help saturating a transistor for 2 amps

    Hi Oldy, Welcome to our forum. ;D It sounds like you are going to connect 78 LEDs in parallel like light bulbs. LEDs are not light bulbs, they are diodes and their individual voltages are slightly different which greatly affects how much current they draw. 4V might be the typical voltage for...
  12. audioguru2

    pnp vs npn?

    Maybe schoolkids need to add and remove electrons at the base of a transistor, but in the real world a transistor is controlled by the amount of its base current.
  13. audioguru2

    0-30 Vdc Stabilized Power Supply

    If you use a 30VAC transformer to allow the output to provide a well regulated 30VDC at 3A, then without a load the unregulated positive voltage will be about +43.8V. Then the total supply voltage for two of the opamps is 43.8V + 5.6V (negative supply)= 49.4V which is too high for 36V and 44V...
  14. audioguru2

    Problem in an H-Bridge

    Hi q12, Your top two transistors overheat because they get hardly any base current so they don't turn on enough. The bottom two transistors have their emitters grounded so when the computer signal goes high to about 4V, the base resistor has 4.0-0.7= 3.3V across it and makes lots of base...
  15. audioguru2

    Sound isnt working!

    An LCD is a type of display, not a product. Which product did you install in your car? A DVD player? I think the audio input is the headphones type of plug but what is it supposed to be plugged into? What is at each end of the AV cords?
  16. audioguru2

    8 way relay board

    The inputs of a ULN2804A are not designed for 5V logic from a computer. It is designed to be driven by Cmos logic that uses a higher supply voltage. I copied this from the datasheet:
  17. audioguru2

    pnp vs npn?

    I don't think about electrons when I have a transistor circuit. I see a resistor supplying base current to turn the transistor on and something that stops the base current to turn it off.
  18. audioguru2

    pnp vs npn?

    An NPN or PNP transistor is turned on by giving it base current. You don't add or subtract voltage. You just give positive current to the base of an NPN transistor and negative current to the base of a PNP transitor. The base current doesn't add or subtract to or from the collector current. The...
  19. audioguru2

    pnp vs npn?

    No it doesn't. The base current controls the amount of collector current in both types of transistors. Also in both, the base current adds to the emitter current.
  20. audioguru2

    HELP NEEDED

    It is a big echo. Exactly the same thing on two different websites.
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