Announcement

Collapse
No announcement yet.

Serbian "Most Wanted"

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • My SMW 555 TX-470nf - 7.7Khz- 8.6 Vac/ RX- 1nf - 8.2 Khz

    Comment


    • This version of oscillator is way better than the typical oscillators in popular VLF builds, but there is also a catch... you can't use it with any coil. The coil for this Tx must float, so it must not have any of the ends connected to a shield.

      In case you build your own coil it is not a problem at all. The op amp takes care that the conduction is precisely 50:50 so the 2nd harmonic will be greatly suppressed, and purity of signal will depend mostly on how the supply voltage is pure.

      The same job would be performed even better with a real balanced oscillator, as you have to have a Tx coil floating anyway. The advantage of a balanced mode operation is that a net E-field of such coil in operation is zero, so capacitive feedback from Tx to Rx coils is off the table and better balance is achieved. With single ended operation a net E-field of a coil is half the voltage across the Tx coil, and capacitive feedback limits the depth of achievable balance.

      Comment


      • By increasing the frequency is not possible to make a primer and becomes unstable with false tone.7-8 Khz works best . amplitude is greater than 10 volts is not stable.

        Comment


        • Originally posted by emoxristov View Post
          My SMW 555 TX-470nf - 7.7Khz- 8.6 Vac/ RX- 1nf - 8.2 Khz
          I can't understand
          you smw 555 tx balance 470nf rx balance 1nf is that so?

          also amplitude 7,7khz

          but 8,6vac and 8,2 khz

          how and where to set?

          Comment


          • These are just all the specifications put together, a 555 audio version, Tx running with 470n at 7.2kHz and producing 8.6Vac, Rx tuned to 8.2kHz with 1nF capacitor (which is the part I don't quite understand).

            Comment


            • add video

              http://www.dailymotion.com/video/xzt...6dd-bobin_tech

              Comment


              • Looks good.

                Comment


                • nice

                  Comment


                  • Help me to analogues of the transistor TIS75

                    Comment


                    • .....
                      Attached Files

                      Comment


                      • BF245B ... it has almost exact Ugso range and it is made symmetrical (drain and source are interchangeable)

                        Comment


                        • Thank you all for your help.

                          Comment


                          • .

                            smw
                            Attached Files

                            Comment


                            • But bd 180 wrong. Turn to 180 degree
                              Attached Files

                              Comment


                              • Where is the problem

                                in my SMW I have problem There is an inverse relationship between sensitivity and volume key . When the sound is low Detecting coin in the air 40cm . When the sound is high Detecting coin in the air 29cm. I use BC517 Instead of MPSA13. help.
                                Attached Files

                                Comment

                                Working...
                                X