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  1. audioguru2

    Solar powered Light

    I have many solar garden lights. Most use an LDR and extra tranaiator to turn the light on and off. Most use a single battery cell. But they are not bright enough to light up anything, just bright enough to be seen in the dark.
  2. audioguru2

    how many 10v leds for 230AC and a few other questions.

    A red LED is 1.8V to 2.2V. A blue or white LED is 3.3V to 3.6V. I have never seen a 10V or 12V LED so maybe it has a current-limiting resistor inside. If you connect AC to an LED then the reverse voltage of more that 5V will destroy it since LEDs operate on DC, not AC. To use AC then you must...
  3. audioguru2

    VOLTAGE DOUBLER

    The 180VAC is 254V peak. If the circuit does not have a load and the capacitors suit the frequency then A-B is 507V, A-C is 760V, A-D is 1013V etc. 
  4. audioguru2

    0-30V Stabilized Power Supply

    When power is applied, D8 does not have enough voltage to conduct but the opamp has positive feedback from R5 nand R6 so it greatly amplifies the noise in the opamp until the output voltage reaches about 10V when the zener diode D8 begins to conduct. When pin 2 rises to +5.6V then the output is...
  5. audioguru2

    1.5v to 5v

    Only 1.5V? I missed that. A CD4047 works down to 3V and a 74HC4047 works down to 2V. My solar garden lights work down to 1V with only two transistors. Their output current is low. The amount of switching time and the amount of supply current that is wasted determines the efficiency.
  6. audioguru2

    1.5v to 5v

    I don't think your oscillator will have a symmetrical output so it will not be a square-wave. Use a Cmos IC oscillator instead. A CD4047 Cmos IC has a RC oscillator followed by a digital divider that produces a perfect square-wave plus a second output that is the opposite (an inverted second...
  7. audioguru2

    VOLTAGE DOUBLER

    Please do not use all capital letters. It is like shouting. Each pair of diodes and capacitors doubles the voltage if the load current is very low.
  8. audioguru2

    Simple FM transmitter question/s + help

    The stray capacitance of the wiring on the pcb will make the frequency much lower than is calculated. Also the capacitance of each transistor is different.
  9. audioguru2

    Simple FM transmitter question/s + help

    My FM transmitter uses a tuning coil with 9 turns, not just 2 turns. My antenna is a straight wire that is 80cm long, not a little coil that will not work.
  10. audioguru2

    Fm transmitter

    The MAX2606 FM transmitter IC comes in a small surface-mount package. It operates at a low current from a low supply voltage so its range is only about 20m. Here is a project: http://electronicsprojects.mediadir.in/?p=1879 It is missing pre-emphasis equalization so it will sound muffled (no...
  11. audioguru2

    0-30V Stabilized Power Supply

    They use extremely low power which shows because they are much too slow. Their output drops above only 800Hz. They are also very noisy.
  12. audioguru2

    Simple, in-line volume control

    A vacuum tube amplifier is damaged when its load resistance is too high. A solid state amplifier does not care if its load resistance is too high. A series volume control is called a rheostat and it can reduce the volume but not to zero. An amplifier has an extremely low output impedance that...
  13. audioguru2

    Final stage amplifier

    Most IC amplifiers have higher distortion than discrete amplifiers because the dynamic heating in the output transistors is passed to the input transistors and resistors which causes the distortion. A half-decent amplifier made with discrete transistors or a very good IC amplifier has distortion...
  14. audioguru2

    Fm transmitter

    It is a garbage circuit that causes interference on many frequencies. It will barely work as an FM transmitter because its 9th harmonic (96.3MHz) is at a very low level. Its fundamental oscillator is at the 10.7MHz of the crystal filter. It is a squarish-wave with many harmonics and the 9th...
  15. audioguru2

    Final stage amplifier

    Barely clipping with low distortion: 1) The TDA2003 has an output of 4.5W into 4 ohms or 8.5W into 1.6 ohms. 2) The TDA2050 has an output of 25W into 8 ohms or 28W into 4 ohms. 3) The TDA7294 has an output of 70W into 4 ohms or 8 ohms. The amount of heat in these linear amplifiers is the same...
  16. audioguru2

    Transistor base current

    The input common-mode voltage range of the inputs of an opamp are the range of voltages that the input transistors work properly. Most opamps have inputs that work when their voltage is between 3V above the negative supply voltage to 3V below the positive supply voltage. The LM358 dual and...
  17. audioguru2

    Help needed urgently: Audio Amplifier Project.

    I think you should look in Google for Class-A, Class-B  and Class-AB amplifiers since your teacher doesn't teach you anything. Also look for "RC calculation for frequency response". Also look for "bootstrapping". Google might have some links for "Audio amplifier Design".
  18. audioguru2

    0-30V Stabilized Power Supply

    You never told us how much current the fan needs. A resistor in series to limit the current might prevent it from starting to run since it needs much more current to start running. The resistor might get very hot unless it is huge.
  19. audioguru2

    Help needed urgently: Audio Amplifier Project.

    9V batteries in parallel make only 9V but with twice as much current available. Your circuit uses two 9V batteries in series to make 18V. The peak current into the 8 ohm speaker is 1A but little 9V batteries cannot supply anywhere near 1A. The currents in your circuit add up to 13.2mA as shown...
  20. audioguru2

    0-30V Stabilized Power Supply

    You are in Ontario, Canada so you can order the proper opamps online from Digikey or Newark. If you order before 8:00PM then they are delivered the next morning. The latest version is designed for the MC34071 or TLE2141 opamps that have inputs that work at 0V and have outputs that go close to...
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