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  1. audioguru2

    perfboards

    With Veroboard I find it easy to change the circuit around or just to change the value of a part because it is like a pcb, each part has its own hole. It is easy also because my solder-sucker works very well and my temp-controlled soldering iron doesn't ruin the printed copper strips.
  2. audioguru2

    My laptop the firebomb

    Lithium burns very hot with a white flame like magnesium, doesn't it?
  3. audioguru2

    Solder Fumes

    No, because the conductors must be heated first so they melt the solder and activate its flux. The solder shouldn't even touch the soldering iron when soldering, except when it flows around the joint. Carrying the solder on the soldering iron would vapourise its flux before it gets to the...
  4. audioguru2

    Buried wire detector

    Hi Alun, You have a good idea to tune the big coil. But I think its inductance would be very low since it is huge and has few turns. Also its Q would probaby be swamped by its driver. Of course the pickup coil should be and can be tuned, then amplified with an amplifier with a high input...
  5. audioguru2

    perfboards

    Hi Prateek, I don't know what you can buy commercially over there, but in North America a breadboard usually looks like this one. It has terminals for a power supply, and consists of many groups of 5 sockets connected in rows. ICs, transistors, resistors, caps and millions of jumper wires...
  6. audioguru2

    4W FM Transmitter

    Hi Guys, I measured the range of my mod4 FM transmitter: about 1km before it was drown by a real station on the same RF frequency. The signal faded when I walked or drove with houses in beween and might travel 5km or more line-of-sight if I had a clear station frequency. It transmits with low...
  7. audioguru2

    0-30 Vdc Stabilized Power Supply

    Hi Costa, With a stronger transformer the ICs are operating with a supply voltage much higher than their spec'd absolute maximum. Also if you set the output voltage low or shorted, with a high current setting, then Q2 and Q4 might melt.  :o C7 if fine with the original value of 10uF. I...
  8. audioguru2

    Buried wire detector

    Hi Kiwi, 1) Your 100Hz is far too low for the inductive loop. Use 5KHz for much better efficiency of your "air-core transformer" and it should be very audible in your earphone unless you are very old and deaf. 2) Using multiple turns on the primary of your air-core transformer steps-up its...
  9. audioguru2

    0-30 Vdc Stabilized Power Supply

    Hi Costa, Welcome to our forum. It is wonderful to hear that your original project works fine and produces 2.5A at almost 34V. ;D It is difficult to believe that its 24V transformer has such a high rectified DC output voltage. Without losses, 24VAC has a peak of 34V and the bridge rectifier has...
  10. audioguru2

    Additional Information

    Yes, (+) on the extension circuit connects to the positive supply.
  11. audioguru2

    Temp. Compensation for linear power supply

    Hi Smart, Thermal shutdown! There's another problem and voltage stability is one symptom of it. Maybe your input voltage is too high. How much? Maybe your heatsink isn't completely flat where the IC mounts, no thermal grease was used or the heatsink doesn't have large fins. What kind of...
  12. audioguru2

    lm7812 problem

    How much more than 1A of output current? Is it hot?
  13. audioguru2

    latching

    Kevin, I don't think my Alternate-Action Pushbutton circuit has a single "preferred" stable state. It has 2 stable states that are both the same due to the symmetrical inputs and outputs of Cmos. I think it will power-up at either stable state in a random fashion. Each time its button is pushed...
  14. audioguru2

    lm7812 problem

    Hi Joe, Is the input voltage at least 15V at its lowest points during ripple from the rectifier's filter cap?
  15. audioguru2

    Additional Information

    Like this:
  16. audioguru2

    oh my goodness

    Hi Rhonn, Noob is short for noobie or new-by (new boy). Someone who is new to the forum but also usually also new to the field of electronics.  ;D
  17. audioguru2

    Additional Information

    Hi Naveed, Sure you can use your replacement transistors. The current is only 10 mA and they won't have more than about 6V across them if you use a 9V battery. The project clearly says to use a single Q1 and Q2 circuit, and series connected LEDs (I don't think more than 2 or 3 in series with a...
  18. audioguru2

    Additional Information

    Hi Nab, This mic should be available in Houston:
  19. audioguru2

    RF Audio/ Video Modulator

    Hi Ldanto, Welcome to our forum. Dazza has a TV transmitter project with a built-in sound modulator here: http://www.electronics-lab.com/forum/index.php?topic=2938.0
  20. audioguru2

    Want Datasheet of Large 7 Segment LED Display

    Google has links to lots of them. Here is the 1st one:
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