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  1. audioguru2

    Linear Voltage Regulator Design

    Of course not. The max output voltage will be 3V to 4V lower than its supply voltage. I don't know what you mean. You'll have to try different values until its transient response isn't too slow, and that it doesn't oscillate.
  2. audioguru2

    What are these abbreviatives mean

    Wow! Thanks, that's great. ;D
  3. audioguru2

    Voltage control oscillator VCO

    Sure good guys make mistakes. The Hubbell space telescope was designed and built by an entire team of experts. Someone made a big, expensive to fix mistake! :o
  4. audioguru2

    MIC coupling capacitor

    A couple of hours ago I surfed just fine everywhere else. Then I came here and pages were very slow and didn't fully load. It was terrible for about 1 hour then suddenly started working fine.
  5. audioguru2

    Linear Voltage Regulator Design

    Hi Staigen, Yeah, the LM358 is blown-up. It is supposed to have a gain of 3.0. I didn't regulate the supply for the opamp because the MC34071 that I recommended and most other modern opamps have a + power supply rejection ratio of about 82dB at the rectifier ripple frequency. So 1V of ripple on...
  6. audioguru2

    Voltage control oscillator VCO

    Hey Sraigen, Thanks. I've been there, done that. It's called experience. 8)
  7. audioguru2

    Photodiode terminals

    Set the multimeter to its "diode test" function and measure the photodiode connected both ways. It will conduct only when its anode is positive, like any other diode.
  8. audioguru2

    What are these abbreviatives mean

    I dunno. C'mon, give us a little hint. ;D
  9. audioguru2

    Op-amp with full swing down to the negitive rail.

    Hi Alun, High supply voltage, rail to rail inputs and output, fast. The LT1498 looks good for this application but costs $6.50US each at Digikey. You are also paying for its low noise. Maybe they throw away many noisier ones. Its details show that its output swings low to 30mV or less. Is that...
  10. audioguru2

    IR photodiode

    Photoconductive mode: You apply a reverse bias voltage to the photodiode which decreases its capacitance increasing its speed. Radiation on it causes it to conduct leakage current. Photovoltaic mode. The photodiode has no voltage across it and connects directly to the virtural ground input of...
  11. audioguru2

    Linear Voltage Regulator Design

    Hi Alun, It is difficult to select U3 for your circuit. It needs inputs that operate near the positive supply, and an output to ground. Cmos opamps do this, but have limited supply voltage rating. If its 10k input resistors were increased so that they have 1.8V or more voltage drop then an...
  12. audioguru2

    Voltage control oscillator VCO

    Hi Walid, 1) The FM transmitter circuit that someone complained about didn't have enough DC negative feedback in its mic preamp to work properly when its battery voltage was above 8V nor if it was below 7V. 2) An ordinary 5V voltage regulator needs an input voltage of 8V or more to operate...
  13. audioguru2

    MIC coupling capacitor

    I am intermittently having great difficulty getting pages to complete opening on this site lately. I need to try 20 and 30 times. When it does complete loading a page so I can read it, when I push the quote or reply button then the same page loading problem happens and I must try over and over...
  14. audioguru2

    Linear Voltage Regulator Design

    Yeah, When you parallel Mosfets then the hottest one increases its resistance so it allows the cooler one to carry more of the current. ;D
  15. audioguru2

    Electronic Stethoscope

    On my old computer's broken hard-drive there is a link I've seen that has a digital display showing heartbeats per minute of an LED shining through a finger. That counter circuit could be driven from this acoustical stethoscope circuit. ;D
  16. audioguru2

    Linear Voltage Regulator Design

    Hi Alun, Those little Mosfets can't dissipate 75W safely, in practise. They are rated for 75W if their case is held somehow at 25 degrees C. You can't find a heatsink that is infinitely large to do the job of perfect cooling, so your heatsink will get hot and you must follow the power derating...
  17. audioguru2

    Linear Voltage Regulator Design

    Hi nearly old man Staigen, You are absolutely correct! I was way off with my selection of high-value "turn-off" resistors for the output transistors in my "fixed" circuit. I have now chosen lower value resistors based on what is inside a TIP120 darlington. I used a 1k resistor in series with...
  18. audioguru2

    Schematic for capacitor discharge projection weld machine

    I compared your project to a car starter motor because they both use high current at low voltage. The wires on a car's starter motor are quite large. Your wires must have about 300 times the cross-sectional area. Bigger than train tracks, I guess. Speaking about trains, A diesel-electric...
  19. audioguru2

    Schematic for capacitor discharge projection weld machine

    Are you serious? The starter motor in your car draws about 100A. Its wires are as big as a pencil. You want 300 times more current? ???
  20. audioguru2

    BENCH POWER SUPPLY

    Your house wiring is 14 guage and is spec'd to carry 15A and supply 1800W. You only have 90W so your cord will be fine. ;D
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