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  1. audioguru2

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

    I buy electronic parts online at Digikey or Newarkinone. A 12,000uF/63V capacitor is $8.45US today.
  2. audioguru2

    UPS calculation....

    Hi Ired, What do you need to calculate? Do you want the output to be square-wave or sine-wave? Do you want to use a 12V car battery? I gave a link to a discussion about a 500W square-wave inverter in your other post.
  3. audioguru2

    Input Jack disables internal sound

    The input jack on the radio has a built-in switch. Simply re-wire it so that the switched wire is connected to your added switch.
  4. audioguru2

    BEL187 NPN Transistor

    Thanks, Sarma. I don't know about transistors made in India. I still have some germanium AC187 and AC188 Philips transistors.
  5. audioguru2

    Inverter Circuit 12V DC to 230VAC Sine Wave

    Hi Ired, Welcome to our forum. ;D A discussion about the calculations for this 500W square-wave inverter is here: http://www.electronics-lab.com/forum/index.php?topic=8609.0 It is an inverter, not a UPS.
  6. audioguru2

    BEL187 NPN Transistor

    Don't you mean a BEL187 and not a BELL 187? Long ago when transistors were new and expensive, they made a BEL187 with high gain and a high max current of 1A. Now transistors are cheap so they are made with high gain but low current and with high current but low gain and you simply use both...
  7. audioguru2

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

    Hi Paulo, Welcome to our forum. ;D I forgot about the 723 regulator IC. I haven't seen one for nearly 40 years. We have a power supply project that uses it but the current isn't adjustable, it is fixed at a max of 2.5A. The circuit you attached is adjustable up to 10A. Its automatic fans are good.
  8. audioguru2

    What the meaning of .....

    New electric/gasoline powered cars are also called hybrids. Two different kinds of flowers combined are also called hybrids.
  9. audioguru2

    What the meaning of .....

    Hi Walid, Sanken makes many hybrid circuits, mostly audio amplifiers. A hybrid is a combination of a few separate parts that are connected together then sealed in a package. It is physically different than a monolithic IC that is one chip.
  10. audioguru2

    My OpAmp Ckt Oscillates.

    Hi WildSwan, You have an unusual opamp. Its output current is 20 times more than an ordinary opamp. It has differential outputs. It is very wideband. The datasheet shows a pin called Vocm that could pickup the output and cause oscillation if it isn't bypassed with a capacitor to ground:
  11. audioguru2

    Inverter Circuit 12V DC to 230VAC Sine Wave

    Then your fans and 60Hz transformer will be overloaded with a load more than about 400W. It is easy to fix. Change the 47k resistor at the CD4047 oscillator to 39k. Did you use a 12V-0-12V 50A transformer? It should be 600VA.
  12. audioguru2

    My OpAmp Ckt Oscillates.

    During your reply, click on Additional Options. Click on Browse to select your schematic from your pc then double click on the file's name to attach it to your reply. Then maybe its input is capacitively picking up its output. Most opamps can't drive a load less than 2k ohms, so 100 ohms is...
  13. audioguru2

    My OpAmp Ckt Oscillates.

    Hi Darwin, Welcome to our forum. ;D You didn't attach your schematic for us to see which opamp, if it has supply bypassing and how it could have a gain of 10 with both inputs grounded. Just about any opamp will oscillate without supply bypass capacitors and if there is capacitance directly...
  14. audioguru2

    Infrared Remote Control

    Yes, the frequency of the 555 oscillator. No. R1 and C1 are just a lowpass filter so the output is DC and not the high frequency.
  15. audioguru2

    Inverter Circuit 12V DC to 230VAC Sine Wave

    Hi Wild Swan, Our original 500W inverter had errors so it didn't work. I helped correct the errors two and a half years ago. My corrected circuit recently was deleted from the project. Which circuit did you make? What happens to its output when it is loaded with more than only 50W? Do you have...
  16. audioguru2

    Infrared Remote Control

    I don't know the spec's for your MOD so I don't know if it is sensitive to a certain frequency. You could make the circuit then experiment with different modulating frequencies to see if it is more sensitive to one.
  17. audioguru2

    Infrared Remote Control

    Hi Walid, We are just guessing about what is inside the MOD. Buy or steal a TSOP from a TV and get its datasheet then you will know what it is and how it works.
  18. audioguru2

    Inverter Circuit 12V DC to 230VAC Sine Wave

    Hi WildSwan, Which circuit did you build? The defective original circuit, the defective "recently corrected" circuit by MP or the one corrected by me two and a half years ago? This is a square-wave inverter, a sine-wave circuit is much more complicated and more expensive. If your fan has a...
  19. audioguru2

    Audiogurus opinion of inverter

    MP. Google's cache of this inverter project shows my corrected inverter schematic there a few days ago. It was recently replaced by yours that has problems. You ruined the project. After you deleted my reply to the person who enquired about making the defective schematic, you had my corrected...
  20. audioguru2

    frequency and transistors

    Hi Student, Welcome to our forum. Opamp manufacturers call the frequency where the response drops -3dB the cutoff frequency. Is it what you call "the upper critical frequency"? Opamp manufacturers call the frequency where the gain is only 1 Unity Gain Bandwidth (National Semi and Texas...
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