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  1. audioguru2

    uestion about the operation of photodiode

    A photo diode can be used to leak a tiny current when it is reverse-biased and light shines on it or it can be used as a solar cell when it generates a tiny voltage and current. When it is reverse-biased it switches faster because the reverse voltage reduces its capacitance.
  2. audioguru2

    Attack site

    My privacy options are set to medium. No cookies are blocked. Today I could not get completely into this site on my first try but I could close it normally. I got in quickly on my second try. All other sites do not have this problem of intermittent access. I think the server here has some dead...
  3. audioguru2

    Attack site

    It happened again just now with IE8: 1) I couldn't get in but instead got the backdrop showing the faint blue schematic. Then I tried Refresh and IE said "not responding". 2) Again I got the backdrop but tried to close IE. IE said "not responding". 3) I got in. I scrolled halfway down the home...
  4. audioguru2

    Attack site

    I use Microsoft Internet Explorer 8 with all the latest updates. Today the access and surfing on this site work perfectly.
  5. audioguru2

    Attack site

    Frequently I cannot get into this site. Frequently when I go to a topic then try to go back to the home page then my Internet Explorer shows "not responding" and nothing happens. I must Control-Alt-Delete to allow me to close the site. My anti-virus software has found viruses on other sites and...
  6. audioguru2

    plz help me out

    A transducer is usually very small and therefore has a very low amount of energy output. There are pressure transducers. There are microphones. Their amount of electrical output energy is almost nothing.
  7. audioguru2

    How to use a BJT as a switch..

    The two projects are connected together like this:
  8. audioguru2

    My latest PCB.

    I made my pink noise generator with a National Semi MM5837 psuedo-random digital noise generator IC (now it is obsolete). I used a few RC networks to convert the white noise into pink noise then I tweaked the values for it to match the output of a very expensive professional noise generator.
  9. audioguru2

    0-30 VDC STABILIZED POWER SUPPLY HELP

    Adding an ammeter in series with the output will ruin the superb voltage regulation of this project. The output voltage of the ammeter will drop with a load. Maybe it can be included in the negative feedback loop to cancel its voltage drop. Instead the voltage across R7 indicates the amount of...
  10. audioguru2

    How to use a BJT as a switch..

    The ultrasonic Radar circuit is not Radar and is not Sonar. It is a simple motion detector with a short range. It has a transistor output to activate an alarm but I don't know which alarm circuit you have.
  11. audioguru2

    Re: UltraSonic Radar

    It is not radar and it is not sonar. The circuit is a simple motion detector.
  12. audioguru2

    Fm transmitter

    The BA1404 is obsolete. It has not been made for 10 years. Where will you buy one? But some kits still use it. There are reviews about it on the web. Don Lancaster says it was a terrible transmitter that drifts its frequency so much that a modern digital tuner cannot receive it. Another review...
  13. audioguru2

    Fm transmitter

    The modern FM stereo transmitters made for transmitting an MP3 to your car radio have an attenuator at their antenna to reduce their range. You might be able to remove or to bypass the attenuator. The lousy old BA1404 FM stereo transmitter IC had terrible performance so it was replaced about 10...
  14. audioguru2

    Fm transmitter

    Look at the graph of voltage and discharge time for an Energizer 9V alkaline battery at a load of 53mA (my FM transmitter's current). In about 2.5 hours the voltage drops to 7V where a 78L05 fails to regulate. But it still can power a low dropout regulator for an additional 11.5 hours.
  15. audioguru2

    re tv antenna amplifier fm/uhf/vhf

    Almost. Every project that I designed worked perfectly the first time. The TV Signal Amplifier was a magazine project. Since it didn't work I went and bought the biggest Yagi all-channels TV antenna that was made and it worked extremely well on a rotor.
  16. audioguru2

    re tv antenna amplifier fm/uhf/vhf

    Our TV Signal Amplifier project is here: http://www.electronics-lab.com/projects/rf/003/index.html It is a very old kit that uses a transistor and subtitute transistors that are obsolete and not available anymore. I made a similar project about 30 years ago. It was badly overloaded all the time...
  17. audioguru2

    Fm transmitter

    The simple FM transmitter circuit has its tuned circuit connected to its antenna which causes its frequency to change if something moves near the antenna. It does not have a voltage regulator so its frequency also changes as the battery voltage runs down. It does not have pre-emphasis like all...
  18. audioguru2

    need help to build my back up concept

    Your English and spelling are horrible. Why not ask questions about your country's weird power cuts on a website in your country in your own language? Here in Canada the electrical company planned for future consumption and it works perfectly all the time.
  19. audioguru2

    Fm transmitter

    My FM transmtter has a range of more than 2km to my extremely sensitive home stereo and car radio. Its range is 300m to my cheap Sony Walkman radio. Its range is 100m to a cheap clock radio. Its range is across the street to a cheap scanning radio from The Dollar Store.
  20. audioguru2

    0-30V Stabilized Power Supply

    The OPA445 opamp is rated for a positive and negative 45V supply which is a total of 90V. It needs a different circuit to the latest one, U2 and U3 use a -5.6V supply and is similar to the original circuit. Its total supply was 48V. A 30VAC/4.3A transformer will be about 31VAC without a load...
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