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  1. audioguru2

    3-colours LED Solar Lights

    Hi Tnk2k, I haven't seen those night lights. Where do you get them? I got my solar lights from Canadian Home Depot. Their importer is also Canadian so they might not be available in the US.
  2. audioguru2

    3-colours LED Solar Lights

    Hi Ante, My neighbours stay up all night watching my LEDs while I sleep. ;D Hey, I received a laser pointer gift for Father's Day! It's in the end of a stainless steel pen with an ultra-bright blue LED. I thought the laser would burn my skin or make me feel some warmth, but no, it only produces...
  3. audioguru2

    Frequency Generator

    Hi, I had good success by using an LM331 V to F generator, a multi-turn cermet trimpot and a regulated supply. It operates at a higher frequency with a stable metalized-plastic timing capacitor so my frequency counter can measure its frequency quickly and accurately. Its output frequency is...
  4. audioguru2

    Audio amp

    Hi Source, What do you want to display? An LM3915 circuit per channel will display output power on 10 LEDs. Each LED shows double the power of the previous one. ;D Whether you need a preamp depends on the level of your music source. At an output per channel of 10W into 4 ohms, the output level...
  5. audioguru2

    555 Timer problem

    Hi Mayooya! ;D
  6. audioguru2

    555 Timer problem

    The minimum supply voltage for an ordinary 555 is 4.5V with a supply bypass capacitor. An LMC555 Cmos version is guaranteed to work down to a 1.5V supply. Maybe the 100uF capacitor has a high current leakage. Try another one. ;D
  7. audioguru2

    MOSFET AMPLIFIER: is it possible????

    Hi Shaiq, I won't do your homework for you, but why not convert the Mosfet-output amp from my post in your other topic, and convert it to all-Mosfets?
  8. audioguru2

    Sound to light / Chaser

    Hi Stuee, Here's our 6-channel AC chaser project: http://www.electronics-lab.com/projects/motor_light/039/index.html A 6-channel (different frequency bands?) sound to light circuit is a different circuit. :( 
  9. audioguru2

    3-colours LED Solar Lights

    Hi Guys, I finally bought some solar garden lights. Hey, they are new and were on sale for about 11 bucks. I can't make them so cheap and look and work as well. They aren't the expensive brushed nickel ones my neighbour has. Those ones light an amber LED very dimly for only a couple of hours...
  10. audioguru2

    LOAD RESISTOR IN A MOSFET AMPLIFIER

    They do turn on at the same time in class-A. That is why they draw supply current. But they are puny little thingys (for speed) with a fairly high "on" resistance. A power Mosfet has thousands of bigger Mosfets, called cells, in parallel. That's why their input capacitance is so high, and their...
  11. audioguru2

    Keys finder circuit

    If it works fine with a power supply then its mic picks up a signal, right? Then what is wrong with your battery? Maybe it can't supply enough current. Not without re-designing the circuit for a separate mic. It is a high gain inverting amplifier, its gain is determined by the ratio of R2/R1 and...
  12. audioguru2

    LOAD RESISTOR IN A MOSFET AMPLIFIER

    Hi Alun, Your Mosfet amplifier will provide only 6.2W to an 8 ohm load at clipping, but draw 600W from a 20V supply. Very inefficient! :o :o An ordinary CD4069 Cmos inverter draws only about 1mA with a 5V supply, about 5mA with a 10V supply and about 10mA with a 15V supply when used as a linear...
  13. audioguru2

    LOAD RESISTOR IN A MOSFET AMPLIFIER

    Hey Alun, You have sketched a "smoke signals" amplifier! ;D Using the Mosfet and its mate that Shaiq is using that are rated for 30A, both complimentary Mosfets would be conducting against each other so hard that if the power supply doesn't smoke, then the Mosfets certainly will. I think it will...
  14. audioguru2

    audio amp

    Hi Fafa, There are many audio power amplifier projects in our Projects section. The link is at the top of this page. Semiconductor manufacurers have many IC amplifiers and show circuits and sometimes even a pcb design in their datasheets. The internet is full of audio projects sites. ;D
  15. audioguru2

    LOAD RESISTOR IN A MOSFET AMPLIFIER

    Hi Shaiq, Before you add negative feedback, you need to calculate the required output current and design a circuit that can deliver that amount of current to the load without much loss. Your output circuit needs to be push-pull, so that it can drive the speaker equally positive and negative. It...
  16. audioguru2

    LOAD RESISTOR IN A MOSFET AMPLIFIER

    What is a drain follower? There are common-drain amplifier stages with a lot of gain that you are using but with a high output impedance, or source-followers (common-drain) with a gain (loss) of slightly less than one but with a low output impedance that you are not using. Why not use both, and...
  17. audioguru2

    LOAD RESISTOR IN A MOSFET AMPLIFIER

    Hi Alun, Good point! ;D 1) Better linearity at high currents. 2) No thermal runaway. 3) Much better high frequency response for low phase shift and more negative feedback. I have made and tested many good high-power audio amps. The best have distortion at full power and less of about 0.01% over...
  18. audioguru2

    telephone related question

    Hi Walid, Thanks, I'm glad to help you understand. ;D
  19. audioguru2

    telephone related question #2

    Hi Walid, Good, now you understand how an electronic phone dials very well! ;D
  20. audioguru2

    Telephone related question #3

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