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  1. audioguru2

    problem of remote jammer

    The value of the 180 ohm resistor in the circuit limits the current in the IR LEDs to only 3mA. Try the circuit with 22 ohms instead. The unmarked pin on the 555 is its pin #7. Tune the frequency with the pot for the best results.
  2. audioguru2

    Audioguru FM Tx

    Hi Walid, Since your circuit transmits hum then maybe your wires are too long and are picking up mains hum. It is important to have very short wires in circuits for VHF frequencies. Side by side wires have capacitance between them. Wires have inductance caused by their length. Extra capacitance...
  3. audioguru2

    6V 5A PSU problem.

    Attach a schematic of the circuit and show parts values. Mark where you measured the ripple voltage. Does the transformer get hot when all DC voltages are loaded?
  4. audioguru2

    12 V DC to a 220V AC Inverter AMplfier Design

    Hi Morro, Four 0.01 ohm resistors in parallel like that is 0.0025 ohms, which is the same as a short piece of wire. It does nothing in the circuit. All power Mosfets have the diode inside as a part of how they are made. In fact, it is a high-power zener diode which protects the Mosfet from d-s...
  5. audioguru2

    How to kill engine noise?

    Hi Wellington, Describe the noise. Is it alternator whine? It changes its pitch with the revs of the engine. The choke coil and filter capacitor should stop it. Maybe you have a ground loop. I bet the 12V zener diode is burnt out. Cars have batteries that charge at up to 14.4V. Anything more...
  6. audioguru2

    Simple O2 meter with LM3915

    But the car's computer doesn't know the difference between a real heater in an O2 sensor or a resistor, does it?
  7. audioguru2

    Simple O2 meter with LM3915

    A 4-wire O2 sensor has 2 wires for its electric heater, so it warms up fast. If the heater burns out or becomes disconnected (by tinkering?) then the car's computer flags an error.
  8. audioguru2

    12 V DC to a 220V AC Inverter AMplfier Design

    Hi Morro, I don't think the 0.01 ohm resistors are required. The diodes are also not needed because power Mosfets have the diode built-in them.
  9. audioguru2

    trasformerless powersupply

    The transformerless circuit supplies a whopping 15mA and is a severe shock hazzard.
  10. audioguru2

    Flyback

    I have taken apart and improved most electronic items I own. My colour TV was one of the 1st things I made work better. But I haven't even looked inside my computer that is 1.6 years old. ;D
  11. audioguru2

    12 V DC to a 220V AC Inverter AMplfier Design

    Use 2 Mosfets and a 200W transformer for a 200W inverter. The IRF540 Mosfet is cheap and common. It can conduct a peak current of 33A. Therefore its RMS max current is 23A. It has a max on-resistance of 44 milliohms which produces a voltage drop of 1.0V. The 10V-0-10V transformer gets a loss of...
  12. audioguru2

    What are discaps?

    All the "discaps" in the kit are ceramic disc capacitors with a fixed value. The "Tuning Gang AM/FM" is actually 4 variable capacitors in one unit for tuning the radio plus it has 4 trimmer capacitors (screw adjustments) for setting it up.
  13. audioguru2

    Convert 0-30V 3A PSU to 5A or more

    A 5.6V, 1W zener diode is tested at 45mA and a 1/2W one at 20mA. They both work fairly well at only 10mA and U1 can supply 10mA without getting too hot, so use 560 ohms for R4 in the original circuit.
  14. audioguru2

    Flyback

    Nope. The flyback transformer doesn't work at the vertical frame rate of 30Hz, it works at the horizontal rate of 15,750Hz (black and white, North America. Colour frequency is slightly different). The beam "flys" quickly from the right side of the screen to the left side for each horizontal line.
  15. audioguru2

    Your next lawn mover!

    Did you see these RC boats? http://media.putfile.com/HydroFoam
  16. audioguru2

    fm

    The transistor's resistors are selected for operation with one supply voltage. If you increase the supply voltage without changing the resistors to compensate for the resulting much higher current then the transistor will get hot and maybe smoke and melt. The collector of the transistor is...
  17. audioguru2

    FM receiver circuit

    Hi Sukhbinder, The CXA1191 is the only "real" radio IC in your selection. My clock radio has an IC like it and it picks up local stations well. Even though the stations are strong, it doesn't overload. The other ICs are garbage.
  18. audioguru2

    12 V DC to a 220V AC Inverter AMplfier Design

    Hi Kachew, Your circuit has the outputs of the unused gates shorted to ground. You have the inputs grounded which is good, but then their outputs will try to go high. Leave the unused outputs disconnected. With the 6 Mosfets, the max continuous output power will be about 600W or more. The...
  19. audioguru2

    Cell Phone "AA" BATTERY Replacement...

    The Lithium-Ion rechargable battery that is made to fit in your cell phone is 3.7V. Most people use it and charge it with the charger that is made for it. Why don't you?
  20. audioguru2

    Cell Phone "AA" BATTERY Replacement...

    It is in a tiny surface-mount package. Can you solder it? Its regulated output voltage is only 200mA which is only 0.74W at 3.7V. The RF output of my cell phone is 2W so its battery power is about 3W at 3.7V. The IC isn't powerful enough for my cell phone. Will it work with yours?
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