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  1. audioguru2

    What the value of Zout???

    I didn't calculate the resonant frequency of the tank but if it is 27mHz then it is an extremely high impedance. Then the circuit will not start oscillating or it will stop oscillating if it has a load.
  2. audioguru2

    Fm transmitter about

    You cannot hear your voice on the radio? 1) Did you use an electret microphone instead of the buzzer on your schematic? 2) Did you connect the electret mic with the correct polarity? 3) Did you correct the wrong wiring on your schematic? 4) Did you tune the trimmer capacitor with a plastic...
  3. audioguru2

    Fm transmitter about

    You said something about 106MHz. Then does the transmitter work good at 106mHz? Can you tune the frequency with the trimmer capacitor from about 92MHz to 106MHz? Is the sound transmitted to an FM radio good? Please tell us what is the problem you have with the transmitter.
  4. audioguru2

    Fm transmitter about

    An FM transmitter is not a parasite. Did you correct your schematic and use the proper parts? What is wrong with the performance of your FM transmitter?
  5. audioguru2

    Fm transmitter about

    The capacitor from the collector to the emitter of the transistor is only 4.7pf. The transistor has an internal capacitance adding to it of about 5pf. But the capacitance between the tracks and wires on a breadboard have much more capacitance between them and at each and every connection. Each...
  6. audioguru2

    Fm transmitter about

    The bottom line in the schematic is 0V from the battery. The emitter resistor and the 22nF supply bypass capacitor connect to it. Make the circuit compactly on a pcb or on stripboard and it will work. It will not work if you make it on a breadboard. It is a very simple circuit so its...
  7. audioguru2

    Fm transmitter about

    1) The circuit is supposed to have a 3V battery. Yours does not have a battery. 2) The circuit is supposed to have an electret microphone. Yours has a buzzer instead. 3) The circuit is supposed to have a 330 ohm emitter resistor. Yours is way too high at 10k instead. 4) The emitter resistor is...
  8. audioguru2

    Pi filter for impedance matching

    A series LC circuit is a low impedance at resonance. The signal current is high. The voltage across its capacitor and the voltage across its inductor is higher than the input signal voltage.
  9. audioguru2

    Transmitting video on radio FM band

    My cheap Chinese RC model airplane has a radio range farther than I can see. Adding a camera and TV transmitter will allow me to see where it is going when it is too far away. For 10km to 15km range then just increase the output power of the transmitters.
  10. audioguru2

    Candle flicker led schematics?

    Like most INSTRUCTABLES, its battery is shown connected backwards.
  11. audioguru2

    Re: Music VU Meter

    I don't like the ballistics of an old mechanical VU meter. I like the electronic peak reading meter instead. The old one allows peaks to be clipped with severe distortion because the peaks are not shown. The peak detector allows the peak voltage to be seen clearly so that clipping is avoided.
  12. audioguru2

    Re: Music VU Meter

    Here is your video:
  13. audioguru2

    Charging / Battery circuit

    I recently replaced the Ni-MH 8.4V (seven AAA cells) battery in my electric RC model airplane with heavier dual 1865 Lithium-Ion cells (18mm diameter by 65mm long). The lithium cells have a lower voltage in theory but provide much more and much longer duration power. The airplane can easily...
  14. audioguru2

    Re: Music VU Meter

    Leds that are turned on for half the time by rectification are efficient only because they are dimmed by the 50% duty-cycle. Most of my LED circuits use pulse-width-modulation for adjustable dimming. But they can increase the duty-cycle to 100% for full brightness, yours cannot.
  15. audioguru2

    Re: Music VU Meter

    My last post shows a copy of your schematic that you posted with green LEDs operating at a low current. Your low level LEDs are bright. But the high level LEDs are dim because they are turned on for such a short amount of time that our vision can barely see them. When the pulse width is less...
  16. audioguru2

    Re: Music VU Meter

    Here is a copy of the fuzzy first JPG schematic you posted on another website. It lights the green LEDs half the time because it is half-wave and does not have a peak detector circuit. The LEDs average only 4mA. The LEDs are a dim blur without the peak detector circuit.
  17. audioguru2

    Re: Music VU Meter

    Don't you know that images at PhotoBucket disappear? Sometimes that website is asleep. But images posted here stay with your thread here and open immediately. JPG file type is for photos not schematics and has fuzzy losses. PNG has no losses and is very clear for schematics. Why don't you...
  18. audioguru2

    Milliamp Question

    You cannot "give" extra current to a circuit that uses only 200mA. The extra current is available and is simply not used. If the circuit is a dead short then it will use all the current that is available.
  19. audioguru2

    Smallest possible LED stoplight circuit

    Yes, you found the CD4017 IC at Digikey. But it is in an extremely small "surface-mount" case that is so small that it is difficult to solder unless you know how. Digikey delivers parts in the US and Canada the next morning if you order before 8:00PM the day before.
  20. audioguru2

    Charging / Battery circuit

    The purpose of the relay and transformers is to keep 240VAC away from the batteries and away from the 36VDC output. But you have them connected together which is a severe electrocution hazzard. Lithium-Ion cells are nominally 3.7V each and are 4.2V when fully charged. Three cells are nominally...
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