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  1. audioguru2

    Question about ttl IC

    Hi Ciao, You didn't check their datasheets? The 74LS247 adds a tail to the numbers 6 and 9. The 74LS192 is a BCD counter. The 74LS193 is a BINARY counter. Your choice.
  2. audioguru2

    0-30 Vdc Stabilized Power Supply

    Hi Newguy, How are you going to stop your batteries from overcharging? Why not use a battery charger IC? That is the most important part of a battery charger. A power supply with voltage and current regulation, like our Lab Supply and fig. 23 of your L200 posting, have completely separate...
  3. audioguru2

    0-20 (3A) and 0-40 (1.5)A Power Supply (Elenco)

    That's right, Kevin. But since the Mosfet is turned-on so hard, it is the same as a 2cm piece of wire.
  4. audioguru2

    0-20 (3A) and 0-40 (1.5)A Power Supply (Elenco)

    Hi Kevin, If you apply a Vgs of only 10V to a Mosfet, then it would be turned-on so hard that the drain would seem like it is welded to the source. But if you apply a Vgs of just a few volts, then a Mosfet would be turned-on just a little, and would act like a constant-current source. The only...
  5. audioguru2

    0-20 (3A) and 0-40 (1.5)A Power Supply (Elenco)

    Hi Ante, HP sold their LEDs manuf. to Agilent, but I think Fairchild makes them too. Cool Blue (clear case) HLMP-CB30. The last 2 numbers are the angle. Its datasheet...
  6. audioguru2

    0-20 (3A) and 0-40 (1.5)A Power Supply (Elenco)

    Thanks Ante, But I'll have to swim nearly half-way around this planet to pickup the purple LED from Greece. And anyway I already have some purple ones that were shipped to me by mistake! I have some HP "cool blue" and green ones that are wide-angle but still are blindingly bright. Your power...
  7. audioguru2

    Electronic parasite zappers

    Today, instead of swatting the mosquito on my arm, I just simply asked her, "What repells you guys?" She replied, "It's those darn lightning bolts that are shown coming from LEDs on schematics"! ;D ;D ;D ;D Me too.
  8. audioguru2

    Electronic Stethoscope

    Hi Prateek, I don't know why an electronic stethoscope produces "an AM kind of waveform" which has many cycles of a low frequency. Since the heart produces pressure pulses, I would expect an AC-coupled stethoscope circuit to produce a single half-cycle at the beginning, and the other half-cycle...
  9. audioguru2

    0-30 Vdc Stabilized Power Supply

    Hi Newguy, If you use this lab power supply to charge a Li-Ion battery then you risk having an explosion and/or a fire!. When a Li-Ion battery is fully charged, it needs a "minimum current" detector circuit to shut-off the charger. This lab power supply doesn't have a method to detect the...
  10. audioguru2

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

    Thanks, Ante, That looks wonderful. I like your nice big filter cap, and especially the name on your schematic!
  11. audioguru2

    0-30 Vdc Stabilized Power Supply

    Hi Emiliano, When you turn the Current Control to the right side and the project current-regulates, then maybe the control is wired backwards and the project works normally if you turn the control to the left side. If the project gives a maximum output voltage of only 26.1V, then its...
  12. audioguru2

    0-20 (3A) and 0-40 (1.5)A Power Supply (Elenco)

    Hi Ante, You are absolutely correct that RDS-on resistance doesn't matter much in a linear circuit. I guess I have "switchers" on my brain lately. But using fewer of the low RDS-on Mosfet IRF5210 is still true because they also have a much lower thermal resistance than your original Mosfets. In...
  13. audioguru2

    Pulse Width Modulation DC Motor Control

    Hi Ante, I'm glad that you agree with me that this project doesn't work. It is really a new topic that you find its oscillator producing a lousy square wave. Kevin also mentioned that his "Classic CMOS 2-inverter Oscillator" makes lousy square waves. But the ones that I have made do not! Why...
  14. audioguru2

    Electronic Stethoscope

    OOOps, Pin 3 of the LM386 was deleted and some wires didn't show on the small JPG. I've fixed them here:
  15. audioguru2

    Pulse Width Modulation DC Motor Control

    Instead of dumping it, at least the project should have a link to this thread.
  16. audioguru2

    Pulse Width Modulation DC Motor Control

    The project is still there, unchanged. Where's my fix for it? ;D
  17. audioguru2

    0-30 Vdc Stabilized Power Supply

    Hi Newguy, Welcome to our forum. Your wish has come true, because we already discussed modifying this supply for 5A. The discussion and detailed instructions are in the other forum, here: http://www.electronics-lab.com/forum/index.php?board=13;action=display;threadid=196
  18. audioguru2

    0-20 (3A) and 0-40 (1.5)A Power Supply (Elenco)

    Hi Suraj, A simple calculation shows that Ante's circuit has 60V input and 5A output, so each Mosfet dissipates up to 30W. If you use a 40V supply, you need only 7 Mosfets. Mosfets with a lower on-resistance such as the IRF5210 would need only 2 or 3 for about the same total cost. It is hard to...
  19. audioguru2

    Electronic Stethoscope

    Hi All, Here's the corrected schematic for this project. ;D Its Parts List will also be corrected soon.
  20. audioguru2

    Schematics Variable current 12v 60A to 0A

    Hi, That's a very fast opamp with a high input impedance. It will have no problem with a single supply. You could use a 10V low-dropout regulator to power it and its oscillator and complimentary emitter-followers that drive the Mosfets' gates. But the very limited spec sheet doesn't show how...
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