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  1. audioguru2

    free energy motor

    Look at the schematics for the Bedini motor. It has a 12V battery to run it and it uses 15A transistors to commutate the battery's power to its drive coil. It is an ordinary brushless DC motor that was made long before anybody wanted a brushless DC motor. Don't be silly. An electric motor...
  2. audioguru2

    Power Supply and Multimeter at 3,3 Ampere...

    Use a bridge rectifier module that is bolted to the metal chassis for cooling. They look like this. This one can be 10A or 35A. I don't know which ones are available in your country.
  3. audioguru2

    OVER-/UNDER-VOLTAGE PROTECTION CIRCUIT ANALYSIS

    The LM393 is a high gain comparator. It is not a low distortion linear amplifier. None of its transistors have negative feedback for linearity. The circuit in the IC probably is as non-linear as an ordinary transistor that doesn't have negative feedback like this one:
  4. audioguru2

    Power Supply and Multimeter at 3,3 Ampere...

    Your transformer can supply only 24V x 3.3A= 79.2VA. The peak voltage is 33.9V so the max average current from the transformer is only 79.2VA/33.9V= 2.34A at its max power rating. The 79.2VA power from the transformer is divided by the rectifier diodes, the power supply circuit and the load...
  5. audioguru2

    RF circuits -> Small Radio Transmitter

    Your link to the FM Modulator picture doesn't work. Please attach the picture here with your reply.
  6. audioguru2

    Im buildin a tachometer an...

    A photo-resistor has a very slow response time. I suggest using a photo-transistor or a photo-diode instead. Divide the number of pulses from the passing fan blades with a digital counter IC. Make a 60 seconds timer that controls the counter/display driver.
  7. audioguru2

    OVER-/UNDER-VOLTAGE PROTECTION CIRCUIT ANALYSIS

    An LM393 comparator has a typical voltage gain of 200,000 when it has a load resistor (National Semiconductor calls it RL) of 15k or more and a 15V supply. If the supply voltage for the load resistor is less then the voltage gain will be less. If the supply voltage for the load resistor is more...
  8. audioguru2

    200W audio amplifier/ Source: Kemo Kits alternate Transistors ??

    Hi Chub, It is not a 200W amplifier. Its text says it produces only 120W into 4 ohms. It does not mention how much distortion. If it produces 120W into 4 ohms then its output would be only about 70W into 8 ohms. It is an old circuit that uses hard to find parts. Why not make a modern circuit...
  9. audioguru2

    NOOB needs help.

    Your switch should activate the input of the monostable timer. It is activating the power supply of the timer and when the power is turned on then the input capacitor triggers the timer because it holds pin 2 low for a moment. R13 does nothing but drain the battery.
  10. audioguru2

    OVER-/UNDER-VOLTAGE PROTECTION CIRCUIT ANALYSIS

    Of course a comparator that has an open collector output needs to have a load resistor. It also needs to have a power supply. I was talking about a complete circuit that works.
  11. audioguru2

    NOOB needs help.

    A transistor inverts the input easily like this:
  12. audioguru2

    Automatic Light System

    I bought a programmable thermostat for my son's new house. It was on sale (half price) for $19.99 and he gets $15.00 back from the natural gas supply company. I also bought compact fluorescent light bulbs for him. They were also cheap but work well and save a lot of electricity.
  13. audioguru2

    Need Help Voltage Regulator 12 vDC using 7812

    A rectifier bridge or four rectifier diodes could be used in a 78xx regulated power supply project. Look at the datasheet of the regulator IC to see the pins layout and to see what capacitors are recommended by the manufacturer. Look at the datasheet of the rectifier bridge or the rectifier...
  14. audioguru2

    Power Supply and Multimeter at 3,3 Ampere...

    Hi Steev, The 0V-30V power supply project will produce a max output voltage of about 25VDC at a max current of 2.3A with your 24VAC/3.3A transformer operating continuously at its rated power rating. The LCD meter project is powered by up to 35VDC. The unregulated voltage with your transformer...
  15. audioguru2

    OVER-/UNDER-VOLTAGE PROTECTION CIRCUIT ANALYSIS

    Hi Walid, You are correct, I was wrong. A BC327 is a PNP transistor. I haven't used BCxxx European transistors for about 35 years and I forgot. Your table does not have correct data. It has the current ratings for the transistors much too high. Check the datasheets for correct max ratings.
  16. audioguru2

    Help! Connecting power supply to small load/solenoid

    Why do you say the solenoid shorts? Does it cause a 6V battery or a 6V power supply to get hot? Does it cause the battery or power supply's voltage to drop? Is the battery or power supply capable of feeding a 1.67A load?
  17. audioguru2

    telephone transmitter again not working??

    Two coils have their turns tight together and their wire must be enamel insulated. The other coil has its turns spread apart so it doesn't need insulation. Tinned wire is easier to solder but the circuit doesn't need tinned wire.
  18. audioguru2

    Help! Connecting power supply to small load/solenoid

    Just calculate the required current by using Ohm's Law. I= 6V/3.6 ohms= 1.67A.
  19. audioguru2

    telephone transmitter again not working??

    I think the parts are too far apart on your PCB which causes high stray capacitance and inductance. The project has a PCB that is much smaller than yours. Why not make it exactly the same?
  20. audioguru2

    white led

    Does your mains voltage change that much?
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