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  1. audioguru2

    Car stereo amplifier

    About 15 years ago there were about 76 car amplifier ICs available from Philips and ST Micro. Now most are obsolete and there are some available in China.
  2. audioguru2

    Car stereo amplifier

    The datasheet for the obsolete amplifier IC tells you EVERYTHING. Didn't you look?? With a 13V supply: 1) As a stereo amplifier the output is 4.5W into 4 ohms per channel with fairly high distortion of 1%. 2) As a single bridged amplifier its output is 12.5W into 4 ohms with fairly high...
  3. audioguru2

    Car stereo amplifier

    The TDA7350A is not available at the two largest American IC distributors (Digikey and Newark) and it is obsolete.
  4. audioguru2

    LM317 Calculator

    Please translate into English.
  5. audioguru2

    0-30V Stabilized Power Supply

    When rectified and filtered, 15VAC makes about 19VDC. The entire circuit will be starved for current unless the values of many resistors are reduced. The maximum output voltage from the project will be about 12V to 14V. The old TL081 has a problem called "Opamp Phase Inversion" which was...
  6. audioguru2

    excess supply current from linear voltage regulator

    The 1A rating of the 9V voltage regulator is its MAXIMUM output current. If its load is 1k ohms then its output current is only 9v/1k= 9mA, not 1A. If its load draws 350mA then the output current of the regulator is 350mA, not 1A.
  7. audioguru2

    0-30 Vdc Stabilized Power Supply

    It is difficult to set each supply to exactly the same output voltage. One supply might be 20.1V and the other is 20.0V. The one with 20.1V will power the load and the one with 20.0V will cause the driver and output transistors to exceed their maximum allowed reverse-bias emitter base voltage...
  8. audioguru2

    0-30 Vdc Stabilized Power Supply

    Each of the two power supply circuits must be COMPLETELY separate from each other. Separate transformer, separate bridge rectifier and separate everything. Do not connect any terminal to earth unless you want it like that. Then you can connect the supplies in series and get up to 60V out, or up...
  9. audioguru2

    PC power supply cellphone charger

    A power supply with a low load current simply idles and does not get hot. A high load current causes a power supply to get hot.
  10. audioguru2

    0-30V Stabilized Power Supply

    Don't you know which parts of the circuit carry high currents? I am interested in circuit design, not pcb design. I design a circuit then send the schematic to a company that does the pcb design.
  11. audioguru2

    PC power supply cellphone charger

    The charging circuit in the phone will draw only as much current as it needs.
  12. audioguru2

    0-30V Stabilized Power Supply

    The traces that carry high currents should be much wider.
  13. audioguru2

    0-30V Stabilized Power Supply

    Newark, Element 14 is Farnell in the US. They sell an MC34071CP for $.484US today which is 0.37 Euros. You are being ripped off.
  14. audioguru2

    ZVS Driver Help

    I see no schematic in your post so I do not know what you are talking about.
  15. audioguru2

    0-30V Stabilized Power Supply

    Each opamp has a different supply current and a different input offset voltage. Select a resistor value that works with your opamp. One trimmer sets the output to exactly 0V when the voltage pot is zero. Another trimmer sets the maximum output voltage to exactly 30.0V. Another trimmer sets the...
  16. audioguru2

    0-30V Stabilized Power Supply

    That is the latest bill of materials but recently we found that the red LED indicates current regulation when it shouldn't. Increase the value of R17 to 47 ohms, 56 ohms or 68 ohms to fix it.
  17. audioguru2

    0-30V Stabilized Power Supply

    It is not cheap, instead it is inexpensive. It is half-way between inexpensive and expensive but it is very high quality. 
  18. audioguru2

    0-30V Stabilized Power Supply

    If you have the voltage pot P1 turned down to zero and C7 is a film capacitor then the VR1 trimmer should be able to adjust the output from about -30mV to about +30mV.
  19. audioguru2

    0-30V Stabilized Power Supply

    Your circuit board is a mess of long wires all over the place. The capacitance between the wires and their inductance will cause problems. Use a compact stripboard layout or a good pcb. I do not see what your meter is measuring. mV? mA? If C7 is electrolytic then it has the "electrolyte...
  20. audioguru2

    power supply schematic with output 72 volt dc, help????

    Every power supply has a maximum allowed output current except the one you want.
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