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  1. audioguru2

    Servo Throttle Control

    Mbedford, Welcome to our forum. I've seen and heard that way to make a fast, smokin' tires launch. You're waiting at the line with the engine revving like crazy, bouncing off the rev-limiter, then the lights change and you pop your clutch, or slam it into Drive. Ouch. Right? Since you want to...
  2. audioguru2

    Problem with mini amp circuit

    Wellington, Good, you have fixed it. Its 47uF input cap must have been shorted or very leaky. Use a 1000uF output cap for better bass with 8 ohm headphones or speaker. 100uf is small for 32 ohm headphones, 220uF would be better. Never mind the Toshiba chip. I forgive the 2nd World War, but I...
  3. audioguru2

    Capacitor

    Quantum, Not much can go wrong with a capacitor, so they are easy to measure: 1) It is shorted. Measure its resistance, it should be open-circuit, or extemely high. 2) It is open, or if an electrolytic, has dried-up. Measure its capacitance.
  4. audioguru2

    Problem with mini amp circuit

    Wellington, Wait a minute, but "loud input with low volume" and "the volume control cracks the sound if it is set too low" both indicate that the volume control may be wired incorrectly. If the volume control's slider is wrongly connected to the x-box's output, then when you turn it down it is...
  5. audioguru2

    Switching power supply

    Vainajala, A darlington transistor does NOT saturate with 2 Vbe voltage drops, when used in a common-emitter configuration that your project needs. Your article refers to the darlington being used in a common-collector (emitter-follower) configuration, where it does have 2 Vbe voltage drops. The...
  6. audioguru2

    Problem with mini amp circuit

    Hi Wellington, Maybe your amp's output is distorted because it is too loud. Turn-down its 10K input volume control. Your very simple amp circuit has nothing in it that gives low distortion. Use a better circuit, like an LM386.
  7. audioguru2

    detector prototype

    Badai, The Eavesdropping Detector project might be sensitive enough to pick-up a nearby transmitting cell phone without tuning, if it isn't overloaded by nearby radio or TV stations. If you could add some kind of tuning circuit to it, you won't know which cell frequency is used. Some cell phones...
  8. audioguru2

    0-30 Vdc Stabilized Power Supply

    Kobus, Welcome to our forum. 1) You can put an LED "power-on" indicator in series with a 1.5K, 1.5W resistor in parallel with R1/C1. Since it draws 20mA, the output current of the project may be restricted to only 2.98A, instead of 3.00A. The difference will not be noticeable. 2) You could...
  9. audioguru2

    0-30 Vdc Stabilized Power Supply

    Capricious, That's good that you finished it and its wiring looks excellent. A few questions: 1) Did you use a 24VAC, 3A transformer? 2) What is the total supply voltage of U2 and U3 without a load? 3) How hot does Q2 get with 5V or less output at 3A? 4) How hot do the rectifier diodes get at...
  10. audioguru2

    0-30 Vdc Stabilized Power Supply

    Capricious, Are we talking about the same circuit? C7 is with the output voltage of this project across it, not R1. R1 is 2.2K ohms, and has the rectified and filtered supply voltage across it. If you are using a 24VAC transformer, R1 will have about 35VDC across it when the project has no load...
  11. audioguru2

    LED Circuit

    Wellington, I know that place, it is a great University.
  12. audioguru2

    True Knight Rider KITT scanner

    Wellington, Welcome to our forum. For many years I have wanted to make your true Knightrider circuit. Its LM3014s fade smoothly between the LEDs, unlike the jerky action of 4017 circuits. I like the way that it slows down the speed of the scanning nearing each end, as it tracks the exponential...
  13. audioguru2

    0-30 Vdc Stabilized Power Supply

    Capricious, R1 is across the unregulated supply voltage. Maybe you mean R2 or R3 gets hot with 3.7V across it. A current meter is connected in series with the load to measure the current that is flowing in the load (and flowing through the current meter). You simply connect a very low value...
  14. audioguru2

    Switching power supply

    Vainajala, Ante, In order to keep the base resistor cool, try a PNP darlington transistor, like a TIP145T, which is rated at 60V. But the 100V rated TIP147T is cheaper, with the same specs. Their data sheet is here: http://www.fairchildsemi.com/ds/TI/TIP147T.pdf With a 10A collector current...
  15. audioguru2

    Switching power supply

    Ante, The darlington transistor that you posted has a max. REVERSE voltage rating of 8V, when its eb junctions have avalanche breakdown like a zener, with damaging results if the current is not limited. Its forward Vbe for BOTH transistors is 2.5V max. at 10A Ic. I was talking about the Vbe for...
  16. audioguru2

    Switching power supply

    Vainajala, I just now noticed that your very high supply voltage will be putting more than 50V on the TL496's output transistors (42V absolute max. rated) when your SMPS has no load! When paralleling the output transistors, connect their bases together, connect the TL494's output transistors...
  17. audioguru2

    was Re:Ir-remote Now is: Op Amp discussion

    Kevin, Put a 'scope on your opamp's output and you'll see that the 1k load resistor to -18V is overloading its positive output swing. Its gain is not reduced, it is current-limiting its output to protect itself against your abnormal load. Which opamp part number? Look at its data sheet to see...
  18. audioguru2

    Switching power supply

    Ante, All the big ordinary transistors have a guaranteed gain of only 5 at 10A collector current. Expensive ones (they select them) have only a little more gain, 10 if you're lucky. Darlingtons don't fully saturate and therefore will need a big heatsink. So I believe that the best thing to do is...
  19. audioguru2

    decoding a 10khz tone!

    Qasim, OK, now you have only one person at a time, so it should work. Any frequency counter will take the analog tone from your FM receiver and display the exact tone frequency. But instead of having a big long number displayed, maybe it is best to just light an LED for the ID of each person. In...
  20. audioguru2

    Switching power supply

    Vainajala, The 150 ohm resistor heats because it has pulses of nearly 40V across it. ON Semi's application circuit shows it being used with an input voltage of only 10V, where 150 ohms will dissipate an average of only about 1/4W. You have a very high supply voltage. The data sheet for your...
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