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  1. audioguru2

    transistor biasing

    If you design a circuit using maximum gain then the circuit will work properly only if it uses transistors that have maximum gain but they might not be available and you must test many transistors to look for them. But if you design a circuit using "worst case" transistors having minimum gain...
  2. audioguru2

    Questions about infrared cordless headphones

    It is a terrible project! I think it is copied from an Indian online magazine. The first transistor in the transmitter has no base bias current so it acts like a rectifier which causes severe distortion all the time. The second transistor also has no bias current and has an LED on its base that...
  3. audioguru2

    0-30V Stabilized Power Supply

    It cannot regulate the voltage when it is regulating the current. It regulates the current by reducing the output voltage until the current is at the same low value as the setting of the current-regulation pot. For example when you short the output to 0V then the output voltage goes to 0V and...
  4. audioguru2

    0-30V Stabilized Power Supply

    The output of U1 pin6 should be +11.2V all the time. Pin2 and pin3 of U1 should be +5.6V all the time. Since the output of U2 pin6 is almost at 0V then the output voltage of the project should also be at 0V because the driver and output transistors are simply emitter-followers with no voltage...
  5. audioguru2

    0-30V Stabilized Power Supply

    No you cannot make two independent supplies because the transformer does not has two completely separate secondary windings. Connect the transformer to make one supply like this: It is not synchronous.
  6. audioguru2

    0-30V Stabilized Power Supply

    The voltage from your transformer is much too high and will blow up most parts. It is 50VAC which makes 68.7VDC. If you use it as a 25V transformer then its voltage is too low but it could allow the project to have a max output of about 26VDC at 3.5A. The minimum transformer voltage for the...
  7. audioguru2

    0-30V Stabilized Power Supply

    With the voltage-setting pot at zero, the current setting pot at maximum and no load, measure the output voltage of each opamp and measure the output voltage of the project and report them here.
  8. audioguru2

    hi plz. help me';;'

    You forgot to tell any details. Is the TV an old CRT, an LCD or a Plasma TV? Is it black and white, colour, high definition or 3D? I got the schematic of my old Sony 32" CRT colour TV from the internet. It is VERY complicated and uses many special SONY ICs. I bought a used newer better Sony TV...
  9. audioguru2

    how to build a quality inverter

    Here are two Switched Mode high frequency power supplies for high power (300 real Watts) car amplifiers. One produces plus and minus 30VDC and the more complicated one produces plus and minus 30VDC. You probably will not be able to find their parts in your country. These power supplies with...
  10. audioguru2

    0-30V Stabilized Power Supply

    Which version did you make? The original one with TL081 opamps? The first modification with OPA445 opamps? The latest modification with MC34071 or TLE2141 opamps? What is the voltage of the negative supply at pin 4 of U3? Did you connect the voltage-setting pot correctly? What is a "heli" pot...
  11. audioguru2

    0-30 Vdc Stabilized Power Supply

    In Picmaster's circuit, RV3 adjusts 0.0V, RV2 calibrates 30.0V max and RV1 calibrates 5.0A max.
  12. audioguru2

    e-bike thesis project

    The motor and/or its speed controller might burn out if the motor has a heavy load (going fast up a steep hill) or is stalled.
  13. audioguru2

    0-30 Vdc Stabilized Power Supply

    I can't find Picmaster's schematic. Maybe he changed all the parts designation numbers. The trimpot connected to pin 1 and pin 5 of the output opamp nulls its input offset voltage so that the project has a 0.0V output when the voltage setting pot is at minimum. The trimpot near the voltage...
  14. audioguru2

    0-30V Stabilized Power Supply

    The two opamps selected for the modified and fixed project are made by two of the largest semiconductor manufacturers in the world. The MC34071 is made by Motorola/ON Semi/ Freescale Semi and the TLE2141 is made by Texas Instruments. You can choose which of these opamps to use. In North America...
  15. audioguru2

    DC Potentiometer in AC circuit to control DC output.

    You drew the connections of the diodes upside-down which makes the bottom wire of the 1000uF capacitor and the bottom wire of the 1k resistor positive. Then the LED has backwards polarity. The 5k pot will probably get hot and burn out.
  16. audioguru2

    12v to 230 volts dc with voltage doubler circuit its possible?

    Since you provided no details about how much power and what waveform are required then I don't think you know anything about an inverter circuit. Why only 45VAC? 
  17. audioguru2

    heavy duty, realiable dc power supply

    Of course a high current, big and heavy power supply costs more than a low current, little and lightweight cheap little power supply. You are supposed to calculate or measure the current then look at the datasheet for the power supply then select current-limiting parts so that you do not...
  18. audioguru2

    how to build a quality inverter

    No details? Since the inverter does not need to provide any output current then it will be simple. Waveform? Voltage regulation? Frequency? Do you know a company that will make the custom transformer? Why only 45VAC?
  19. audioguru2

    heavy duty, realiable dc power supply

    A cheap linear power supply dissipates exactly as much heat as an expensive linear power supply. Redundant components do nothing. A big heatsink with many fins distributes the heat to the surrounding air.
  20. audioguru2

    heavy duty, realiable dc power supply

    No, it is a linear power supply with no output ripple but its driver and output transistors get very hot so they need pretty big finned heatsinks. A switched-mode power supply has high frequency ripple and its regulation is not as good as a linear regulator. But it does not heat much.
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