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  1. audioguru2

    Electronic Stethoscope

    PM from Narmadha: hi can u send me the picture of phone jack used in the e- stet 2 .. Hi Narmadha, I am sorry that the pic I posted of stereo headphones dissappeared from this thread. I don't know what happened to it. I found it in my recycle bin. You should use headphones that completely cover...
  2. audioguru2

    frequency and voltage in DC motor

    Hi Duratia, RMS is used to calculate the amount of work done by a sine-wave. The peak voltage of a sine-wave is much higher than its average voltage. The peak voltage of a square-wave is the same as double its average voltage. The average voltage of a PWM circuit is the peak voltage times the...
  3. audioguru2

    0-30 Vdc Stabilized Power Supply

    Hi again Rodrigo, Before your supply's problem was that its output voltage was too low. Now it is too high. What happened that changed it? Is Q2 or Q4 shorted? What is the output voltage of U2 when the voltage control pot is turned down? It is normal for it to go low but U2 will overheat if left...
  4. audioguru2

    Sine Wave Output on the IC8038 Circuit

    Hi Dennis, Intersil have application notes about their ICL8038 and Maxim have them about theirs. Here is part of a note from Intersil: http://www.datasheetarchive.com/semiconductors/pdfdatasheet.php?Datasheet=933731 I didn't know that you are a fairly old grasshopper. I thought you are a young...
  5. audioguru2

    Transformer and LM317 Question

    Hi Indulis, The heatsink tab is connected to the output terminal of an LM317. To avoid having output current in the wire connected to the voltage-setting resistor, my LM317 project uses the tab as the output terminal and the output pin for the voltage-setting resistor. Then the voltage...
  6. audioguru2

    Sine Wave Output on the IC8038 Circuit

    Hi Dennis, A TL071 is similar to an LF351 opamp since they both have difficulty with signals over 100kHz. 1MHz is a radio frequency so long wires can ruin the performance of your project. The parts on your perf board are very far apart causing series inductance in the long wires between parts...
  7. audioguru2

    frequency and voltage in DC motor

    If the PWM signal has fast rise and fall times, I think the two frequencies would operate a DC motor exactly the same. I haven't tried it, but I think that the inductance of a DC motor would limit its current if a much higher PWM frequency is used.
  8. audioguru2

    Input signal for LM3915. need help.

    Hi Ryeeson, Modifying my circuit to work as an average detector with a single supply probably won't work. I have deleted its circuit.
  9. audioguru2

    Sine Wave Output on the IC8038 Circuit

    BTW, the old LF351 opamp is also contributing to your problem. I've never seen one.
  10. audioguru2

    Sine Wave Output on the IC8038 Circuit

    Hi Dennis, Welcome to our forum. ;D Didn't you look at the datasheet for the old ICL8038? I used it in 1975 and its lousy performance was pretty good in those days. Maxim has their newer MAX038 which is an improvement.
  11. audioguru2

    230V AC to 12V DC @90 AMP

    Hi Mr. Madam, HotWaterWizard in drag? ;D ??? The tiny surface-mount diode would probably vaporize, and the transorb is a zener, not a diode. Use high voltage fast diodes with about a 5A continuous current rating. I don't work with kW stuff so I don't know any.
  12. audioguru2

    Transformer and LM317 Question

    If you compare the old LM301 with the newer TL081 you will see that the LM301 needs the 100pF capacitor but the TL081 won't work properly with it. Remove it. You have selected a circuit that reduces the charging current when the battery's voltage and current reaches amounts set with pots. You...
  13. audioguru2

    230V AC to 12V DC @90 AMP

    Hi Madam (really?), You could easily make AC in the high frequency side of the tramsformer if it is center-tapped, and each end is driven with push-pull Mosfets. Then the transformer is never turned off so the flyback voltage is reduced significantly. The voltage peak is doubled across the...
  14. audioguru2

    Speaker Electronis Problems

    Hi Suveran, Hela. Your English had severe breakdown for one post while you were yapping with Ante. Two bass speakers in one box would make a huge box. You could use coils and capacitors to make a passive stereo crossover network for the speakers but the mid/high speakers will be too loud and...
  15. audioguru2

    Speaker Electronis Problems

    Hi Suveran, Welcome to our forum. ;D Your English is fine. You want to make a crossover network, also called x-over. It keeps the bass out of the mid/high speakers and keeps the mid/high sounds out of the bass speaker. You have two channels but only a single bass speaker. You can't short...
  16. audioguru2

    Transformer and LM317 Question

    Hi Indulis, Thanks for your correction. ;D
  17. audioguru2

    230V AC to 12V DC @90 AMP

    Does your DIY transformer even work at a frequency as high as 25kHz? An ordinary power transformer doesn't. It is a special art to make an audio transformer that works well up to only 15kHz. High frequency. high power transformers use a ferrite core. If you don't understand about the flyback...
  18. audioguru2

    230V AC to 12V DC @90 AMP

    No way, man. Transformers work with AC, not DC.
  19. audioguru2

    230V AC to 12V DC @90 AMP

    Hi Madam, Your circuit applies 325VDC to the primary of the transformer. If the mosfet conducts enough current then the transformer would be saturated and operate like a piece of wire. Each time the Mosfet turns-off at 25kHz it has thousands of positive volts across it due to the inductive...
  20. audioguru2

    Transformer and LM317 Question

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