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    Design of Stepdown transformer 3 Amp 12VDC from 230V AC mains.

    Hi, As a starting point have a look at this site. http://www.ee.surrey.ac.uk/Workshop/advice/coils/#cor Then you can ask more specific questions regarding transformer design. Regards
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    Need sugestions about virtual ground or symetric supply for OPAMP

    hi, Have a look at www.analog.com site and search for 'phantom ground'. Application note: AN581
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    Transformer

    This same question, by the same OP has been asked and answered in detail on another forum.
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    0-30volts Lab power supply

    hi pier, Assuming that the existing 10K pot gives you a linear range of 0 to 30Vout, then the 100R [centred] will give you a +/- 0.15V adjustment, that should be OK.
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    freq VS voltage

    hi, Most domestic mains supplies are single phase, either around 110Vac or 240Vac. The mains frequencies are around 50 or 60HZ. For example, if a mains transformer was made for the UK, the primary winding would be 240Vac, in the USA 110Vac. Most mains transformers will work OK, with 50 or 60HZ...
  6. E

    help!!!

    hi henry, The T(t) is the instantaneous Torque of the motor with respect to time and its composed of the 'B' and 'J' Torque, B component is due to the angular rotation and the J component is due to the acceleration of the motor, both with respect to time. If the motor is at a steady angular...
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    parallel port not working

    hi pier, If your PC's parallel port is not accepting commands, it maybe your operating system. Are using Win XP?, if yes, then it will block access from your program to the port. If required download from the web 'inpout32.dll' and place it in the Windows/System directory. Also check your...
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    12v to 230 volts dc with voltage doubler circuit its possible?

    hi, You say that you want to power a PC from the output? This will mean, if you are using a standard 'desktop' PC it will have to be 230Vac at 50/60HZ. Its possible to buy a +12Vdc to Mains invertor, rated at say 300Watts, that will drive a PC. The circuits you have posted are for doubling...
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    Question: Can computer burn your house down?

    hi, I would recommend that if any electrical appliance can be switched OFF, it should be switched OFF, whenever, the premises where the equipment is located are unoccupied. Obviously certain equipments have to be powered ON so that they can give a 24/7 service. The important aspects of energy...
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    Volt/Ammeter LCD panel into Powersupply

    hi bb, The capacitor is C1. J4/3 is the ground [0V] connection for the VM gnd. J4/2 is measuring the voltage drop across R7, the psu current sense resistor. J4/1 is measuring the  voltage output of the psu. J3/1 is the Vsupply to the the VMeter. The fact that C1 is drawn as a non -polar cap in...
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    Feed back amplifiers

    hi, Look thru the www.analog.com site, they have many application notes that you may find useful.
  12. E

    help me read this circuit? please?

    hi quincy, Its just another symbol for ground, 0V ref for the +/-Vcc supplies. Does that help?
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    PIC won't work with capacitors

    hi, Look at  page 93 of the 16F62X datasheet. Are you using a series or parallel cut crystal?  also note the possible requirement for a series resistor in one leg of the crystal. Have you correctly configured the PIC using the _CONFIG, to suit your crystal?
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