Search results

  1. audioguru2

    Help identify unknown component

    This SBS is spec'd to conduct when the voltage across it rises to 8V without a gate signal, and less voltage with a gate signal. The PNP transistor has a small leakage current that is amplified by the NPN transistor. Then the current of the NPN transistor is amplified by the PNP transistor and...
  2. audioguru2

    Difference b/w Electrate and Condensor mikes

    Some electret mics are 2-wire and some are 3-wire. They connect to the circuit completely differently. Your replacement mic isn't an electret type, doesn't work or isn't wired correctly to the circuit. The problem isn't a different sensitivity.
  3. audioguru2

    Difference b/w Electrate and Condensor mikes

    If you spelled "electret" correctly then you could have looked at its operation in Google. The electret material holds a high voltage charge which allows the mic to work. A condenser mic doesn't have the charge so needs an external high voltage power supply (48V) to work. Many people wrongly...
  4. audioguru2

    0-30 Vdc Stabilized Power Supply

    Great! You made a good fix. ;D
  5. audioguru2

    12 V DC to a 220V AC Inverter AMplfier Design

    Look in Google for "ferro-resonant transformer". It has a third winding that is tuned by a capacitor to be a tank circuit. It is designed so that its core saturates which makes voltage regulation but a square-wave, then the tuned winding converts the square-wave to a sine-wave.
  6. audioguru2

    Rechargeable battery - Rate of Self Discharge ?

  7. audioguru2

    What are FETs, Diacs and Triacs???

    There are explanations for most electronic devices in our Articles section. Google can direct you to other sites with good explanations.
  8. audioguru2

    12 V DC to a 220V AC Inverter AMplfier Design

    A Class-C amplifying transistor conducts only part of the time so has very high distortion. Radio circuits use them because they can tune the LC load to substatially reduce the distortion. 50Hz or 60Hz is such a low frequency that an inductor and capacitor to tune to the low frequency with high...
  9. audioguru2

    12 V DC to a 220V AC Inverter AMplfier Design

    Your idea of using a linear sine-wave generator wastes a lot of power as heat. Even if the high current output of the generator operated in Class-B to save power when the load was low, it would heat about the same power as the load at full output. Half the power from the battery would be wasted...
  10. audioguru2

    Knight Rider with Halogen Bulb

    It will ocasionally have about 11V across it. So its momentary dissipation is 11V squared/27 ohms= 4.5W. The percentage of the total time that it is turned on determines its average dissipation. 1W? 2W?
  11. audioguru2

    Knight Rider with Halogen Bulb

    Your new circuit is correct. Add a 1k resistor to quickly turn off the TIP42.
  12. audioguru2

    Knight Rider with Halogen Bulb

    Look at the spec's of the transistors to see why it doesn't work. The halogen bulb draws more than 4A when hot, much more when cold. The TIP42 and most other power transistors need at least 400mA of base current to saturate with a 4A load and has a min current gain of only 12 at 4A. The 1k base...
  13. audioguru2

    12 V DC to a 220V AC Inverter AMplfier Design

    A 220VAC sinewave is 622Vp-p. A Class-A amplifier uses its full power whether it is fully loaded or not, so becomes extremely hot and wastes as much power as it delivers at full load. It is a total waste of power at low loads. Think about using a Class-D switching amplifier that is very...
  14. audioguru2

    Soldering: what am I doing wrong?

    You can't mix "lead-free" soldering acessories and irons with ones used for leaded solder! Maybe that is your problem.
  15. audioguru2

    Help identify unknown component

    Yes. It is also called a Triac.
  16. audioguru2

    0-30 Vdc Stabilized Power Supply

    Then Q2 or Q4 leaks. Probably Q2 from being fried. Measure the output voltage at pin 6 of U2. It is probably negative in its attempt to reduce the output voltage down to normal.
  17. audioguru2

    0-30 Vdc Stabilized Power Supply

  18. audioguru2

    Surround Sound for car audio

    That article is wrong and messes up a car stereo. They just want you to pay $10.00 to see their simple schematic. 1) Connecting speakers in series doesn't change their phase 15 degrees or any other number of degrees. 2) Connecting speakers in series loses most of an amplifier's power. 3) With a...
  19. audioguru2

    Simple help with transistors!!

    The LED won't light when it is shorted by the other switch contacts.
  20. audioguru2

    Want to power up my programmer

    Hi Shaiq, The output voltage of a cheap unregulated adapter changes with its amount of load. The max input voltage to an LM317 is more than 40V. But then it gets hot which might limit your circuit's max input voltage.
Top