Search results

  1. audioguru2

    Surround Sound for car audio

    The circuit can be modified simply to use a single supply as I showed before. It doesn't need a total of 24V, the TL072 opamp works fine with as low as 7V. The signal voltage is nowhere near as high as 24V. You missed joining some parts on your schematic. The center and sub-woofer are not the...
  2. audioguru2

    Surround Sound for car audio

    Opamps don't need a positive and negative supply. They just need their inputs biased at a voltage that is half-way on a single supply. Then they would need bias resistors and coupling capacitors. As the coupling capacitors charge when the power is turned on, the speakers would probably make a...
  3. audioguru2

    Low-pass Filter?

    Then you might need to select them for high gain and also select 2N3055 transistors for high gain. With a 500W load, the battery current is 50A. Therefore the 4 sets of output transistors pass 12.5A for each transistor. The minimum current gain for a 2N3055 is 5 with a 10A collector current so...
  4. audioguru2

    0-30 Vdc Stabilized Power Supply

    Hi Patrick, The +32V and the -5.6V are in series and add to 37.6V across the total of 11.5k resistors. Q1 is off in this circuit.
  5. audioguru2

    Simple help with transistors!!

    You don't want the transistor switch as an emitter follower. It switches better when it is a common emitter stage. My transistor switches the LED with its resistor and the buzzer to the 12V battery. They are in parallel.
  6. audioguru2

    Electronic formula's ???

    Are you studying to be a Mosfet designer? Your school quiz isn't practical to most people.
  7. audioguru2

    Simple help with transistors!!

    If you connect the 12V LED to a 12V battery then it lights. If you connect a 12V buzzer to a 12V battery then it buzzes. If you connect the LED and the buzzer to the battery then they are in parallel aren't they? Why connect an LED to the base of a transistor? The LED doesn't turn itself on and...
  8. audioguru2

    0-30 Vdc Stabilized Power Supply

    Where is 26.4V? If the transformer is only 24VAC (much too low for this project) then its peak voltage when loaded is 33.9V. The rectifier bridge drops it about 2V at full load and the main filter capacitor will have a little ripple making a positive supply of about 32VDC. 46k is much too high...
  9. audioguru2

    Electronic formula's ???

    Are the W1 and W2 wavelengths? Why aren't the inductors L1 and L2 shown with their values measured in Henries?
  10. audioguru2

    Low-pass Filter?

    Don't make an inverter with the wrong output voltage so that the peak of its square wave is the same voltage as the peak of a sine wave. If it powered heaters or lights then they would have way too much voltage.
  11. audioguru2

    datasheet search

    I learned the part numbers of parts by looking at the lists in suppliers' catalogs. The lists for transistors are catagorized in order of voltage and current ratings. The prices are also shown. 600mA might be the average current of a DC motor but its max current might be 3A. Then if 40V is high...
  12. audioguru2

    hex inverter

    A Cmos CD4069 hex inverter IC is frequently used as a two-inverters oscillator, and with a resistor providing negative feedback as a linear amplifier.
  13. audioguru2

    0-30 Vdc Stabilized Power Supply

    Here is how Q1 works and how the negative 5.6V supply works:
  14. audioguru2

    0-30 Vdc Stabilized Power Supply

    Hi MonSSter, In your reply #931 all 3 terminals of Q4 were at +32V and the output of U2 was at 0.4V. So I thought that Q4 was shorted. Now with R15 disconnected the base and emitter of Q4 dropped to +0.5V which is normal. The output voltage of U2 is high which is normal without R15. Is U2 still...
  15. audioguru2

    0-30 Vdc Stabilized Power Supply

    Q4 is shorted and might have destroyed the new U2 and Q2. Remove R15 and get Q2 and Q4 working properly first. As a test, connect two 10k resistors to the base of Q2. Connect one resistor to +34V and the other resistor to the output's 0V. Without a load, the output voltage should be about...
  16. audioguru2

    Why does a transistor heat when base current is high

    The relay coil is an inductor. An inductor creates a very high voltage when its current is stopped, the voltage can destroy its driving transistor unless a diode is connected across the relay's coil in reverse to arrest the voltage spike. Heating is caused by the voltage across the transistor...
  17. audioguru2

    HELP - resistors and dip-switch

    You can use the fan's driving transistor as a completely quiet variable resistor, then it gets hot. You can use PWM at a frequency above 20kHz so it is completely quiet, and it doesn't get hot. You can use a bigger fan that can turn slower to move as much air as a smaller fan running faster, and...
  18. audioguru2

    Why does a transistor heat when base current is high

    Which transistor? Why is the base current high? What amount is the base current? What amount is the collector current? Why doesn't the transistor have an adequate heatsink?
  19. audioguru2

    Low-pass Filter?

    Yes, the CD4047 has a frequency divider so its outputs are a perfect square wave. The CD4047 is Cmos so with its very light load its output voltage swing is the supply voltage. A 555 doesn't make a perfect square wave. The CD4047 circuit is perfect, simple and cheap.
  20. audioguru2

    Digital radar speedometer

    That is another way to do it. Who is going to design a circuit that works that way?
Top