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  1. audioguru2

    0-30 Vdc Stabilized Power Supply

    Hi Roelli, I'm glad to help fix this project. Some people made a supply with two 0.1 ohm resistors and one 2N3055 was hot and the other was cold. Transistors are all different. One had a high current gain and the other had a low current gain. Changing the resistors to 0.33 ohms allowed the...
  2. audioguru2

    0-30 Vdc Stabilized Power Supply

    Hi Roelli, Welcome to our forum. ;D It is good to hear that your project works great, but it is too bad that you are worried about it dying. The LED lights whenever the load current exceeds the setting of the current-regulation pot. Maybe you will need its current regulation and don't want it...
  3. audioguru2

    Bridge problem!

    It is oscillating at a low frequency. I think it has way too much voltage between outputs because it isn't the IC selected for being a bridged amp which would have a very low voltage between outputs. The voltage between its outputs causes a high supply current which might reduce the supply...
  4. audioguru2

    Bridge problem!

    Thanks. It is much clearer and uses many fewer bytes. Its minimum supply voltage is 8.0V and it uses a very high current at full output. If your supply is a little 9V battery then it won't work. What is the DC voltage at pin 8 and at pin 10? What is the impedance of the speaker? What is the...
  5. audioguru2

    Bridge problem!

    Your very fuzzy schematic is a copy of the one in the datasheet so it should work. It would be clearer if you saved it at a GIF or PNG file type. You saved it as a huge JPG file type which is used for photographs. The polarity of the electrolytic capacitors are shown with the solid bar as the...
  6. audioguru2

    shake light

    A flashlight that you shake, which makes a magnet move inside a coil and generate a little amount of power? Do they actually work? Guys have found ordinary batteries hidden inside! I tried shaking one in the store for a long time and I thought my arm was going to fall off. Then its LED was...
  7. audioguru2

    Bridge problem!

    Hi Mukhalled, Attach the schematic of your bridged TDA2005 for us to see what is wrong with it. The only difference on the datasheets between the TDA2005M (for a bridged amp) and the TDA2005S (for a stereo amp) is that the TDA2005M is selected for a max output offset voltage of 150mV. Then it...
  8. audioguru2

    shake light

    What is a "shake light"? What does it do? What is in it?
  9. audioguru2

    FM impedance antenna matching

    If you connect an antenna directly to Q1, then the antenna becomes part of the tuned circuit and the frequency will change all over the place if anything gets near the antenna. On my FM transmitter, I used a buffer transistor to isolate the antenna from the oscillator. Also on my transmitter, I...
  10. audioguru2

    Difference b/w Electrate and Condensor mikes

    What amplifier? Your condensor mic will have about the same sensitivity as an electret mic if you bias it with 48V and have its proper load resistance. Look at the datasheet for the mic.
  11. audioguru2

    12 V DC to a 220V AC Inverter AMplfier Design

    Maybe your load doesn't need a sine-wave and will work from a simple square-wave inverter. A "modified sine-wave" inverter has a square-wave with a step in it and isn't too hard to make.
  12. audioguru2

    Simple O2 meter with LM3915

    Hi Mr. Super Headbanger. Wilson, isn't it? The O2 sensor in a car normally produces a fluctuating voltage. One meter circuit on the web uses an opamp buffer driving a 2.7M resistor, a 0.1uF capacitor to ground then another opamp beffer. Do the same thing with a 270k resistor from the O2 sensor...
  13. audioguru2

    Knight Rider with Halogen Bulb

  14. audioguru2

    12 V DC to a 220V AC Inverter AMplfier Design

    Class-D switching amplifiers are complicated. Ones for audio use a fairly low supply voltage. TI has an IC with up to only 240W output. A sine-wave oscillator would drive a class-D amplifier which would drive a stepup transformer.
  15. audioguru2

    Knight Rider with Halogen Bulb

    Hee, hee.  ;D When do they let you out of jail?
  16. audioguru2

    infrared sensor

    The spec's and pin functions of devices are on their datasheets. If you don't know their part numbers then you won't know their spec's. An IR LED is a 1.4V diode that is easy to measure its polarity. A two-wire IR detector could be a photodiode or a phototransistor and is easy to measure which type.
  17. audioguru2

    Simple O2 meter with LM3915

    The car O2 meters in cars that I have seen use the linear LM3914 IC and not the logarithmic LM3915 IC. Two LM3915 ICs have an input voltage range of 1000:1. Two LM3914 ICs have an input voltage range of 20:1. The output voltage of an O2 sensor oscillates between the positive supply and ground so...
  18. audioguru2

    Knight Rider with Halogen Bulb

    But a "flash trail" means that the output transistor will be operating as a linear amplifier and getting very hot. You could do it with PWM and it would remain cool.
  19. audioguru2

    12 V DC to a 220V AC Inverter AMplfier Design

    It is not good to make an inverter that wastes as much power as the load uses. An inverter should be efficient, and use a switching amplifier instead of a linear amplifier.
  20. audioguru2

    DIY Power conditioner (for mains 230V)?

    The performance is determined by the cost. Some cheap "power line conditioners" consist of a pair of cheap MOV's that slice off spikes. Some expensive UPS's use a custom-made very large and expensive tuned ferro-resonant transformer that regulates the AC voltage and fills-in short duration loss...
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