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  1. audioguru2

    Sound to Light Effect

    1) The first opamp is inverting with such a low input resistance of 1k ohms that it kills most of the signal from the higher resistance electret microphone. This opamp should be non-inverting with a much higher input resistance. 2) The coupling capacitor C4 between the opamps couples positive...
  2. audioguru2

    About file uploading

    It looks like the new software for this site does not allow an attachment to be made so we will never see the schematic. There is a button here that says, "Insert other media" that might allow an attachment. I am attaching a box that says "TEST". No, it allows only attachments that were made...
  3. audioguru2

    6V Ultra-Bright LED Chaser

    For anyone who has the same problem that I discovered and fixed. I designed this project almost 10 years ago. This problem occurred on two projects that were 8 and 9.5 years old. The first LED remained lit when it should be turned off and each blinked LED had a light trail behind it. The cause...
  4. audioguru2

    Variable Power Supply With LM7812

    This new project is here: http://www.electronics-lab.com/projects/power/026/index.html It has some serious errors: 1) It says and shows LM7812 but it links to the datasheet of an L7812 that is different. 2) It does not say its adjustment range of output voltage. 3) The datasheets of the L7812...
  5. audioguru2

    Blank screen when I try to reply

    I recently received two e-mail notifications to replies to a topic I participate in but clicking on the link shows a blank screen. Here is one link: http://www.electronics-lab.com/forum/index.php?topic=7317.new;topicseen#new When I find the topic in Recent Posts the same blank screen occurs...
  6. audioguru2

    My Sound Level Indicator project

    I don't believe it. Two series connected LEDs in my project  http://www.electronics-lab.com/projects/motor_light/002/index.html don't work anymore. They are the second-lowest ones so they have been turned on most of the time at about 25mA for nearly 6 years. I thought the LM3915 driver IC had...
  7. audioguru2

    More and more SPAMMERS

    Could somebody please get rid of all the new SPAMMERS who are trying to sell cheap Chinese shoes here? Why do they come here? Are they wierd people or are they robots?
  8. audioguru2

    SPAMMERS

    Please get rid of all the SPAMMERS today. Can't we prevent a new SPAMMER from posting "millions" of times?
  9. audioguru2

    Too many SPAMMERS here

    Why does this site allow a new member (a SPAMMER) to post many threads or many replies to old threads? This morning I received e-mail notices of many replies to very old threads. They were all from one new SPAMMER who deleted all his replies. The Most Recent Topics index is jammed full of SPAM...
  10. audioguru2

    Spammer who is selling illegal drugs

    Could somebody please delete the many posts and ban the SPAMMING idiot who is recently selling illegal drugs here.
  11. audioguru2

    Virus warning

    Each time I log in here or navigate and on two other electronic chat sites I get a virus warning. I can log in and navigate without the warning on many other sites.
  12. audioguru2

    New Spam

    There is another SPAMMER selling fake Viagra on the High Voltage forum. Luckily it is not a virus (or maybe it is). When was the last time a real thread was posted on the High voltage forum? A few of years ago? Many topics have been SPAM. So it is time to close the High Voltage forum and let...
  13. audioguru2

    Plants Watering Watcher-2

    My daughter said that hers stopped working and needs to be fixed. Its LED did not light when it had the high resistance of dry soil or nothing between its probes. Duh! Its 3V battery was only 0.45V. It probably stopped working months ago. A pair of new AAA alkaline cells fixed it.
  14. audioguru2

    There is a trojan pc virus here today.

    I entered this site 3 times today. Each time my anti-virus software reported receiving the same trojan virus that it deleted. For months this site has caused my Internet Explorer to report "Not responding" when I try to navigate and I must "Control Alt Delete" to close it and get away.
  15. audioguru2

    Re: Wave Bubble?

    If somebody tracks you with a radio transmitter attached to your car then if you make a jammer they can also track the jammer. A jammer on a car will cause an awful lot of interference to a lot of people.
  16. audioguru2

    Re: dc power supply, 5v 5amp

    A PNP power transistor can be added to a 7805 or LM317 regulator to boost the output current. The simple circuit has no current-limiting. Here is the circuit:
  17. audioguru2

    Re: need help please..

    A log potentiometer is a volume control. If you use a linear pot then most of the volume change will be at its low end and from half to max will make very little difference in volume.
  18. audioguru2

    Are datasheets important?

    Our Low Cost 500W Inverter project uses a CD4047 oscillator IC which divides the oscillator frequency by 2 for a 50Hz output from the inverter. The project originally used a 100 ohm resistor and a 4.7uf capacitor for its 100Hz oscillator. Somebody (a God) changed the resistor's value to 1k. Is...
  19. audioguru2

    This site is very slow lately

    Have other people noticed that this site is very slow lately? It opens slowly. It navigates slowly. You type a reply then it takes "forever" to post it. Maybe that is why there are not many posts anymore.
  20. audioguru2

    Auto dimmer

    A quick search in Google found many good "darkness activated relay" circuits like this one:
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