KrNews #08 05 марта 1999

Железо

Ferrum! - Seeker flush on the basis of a digital multimeter.

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      FINDER HIDDEN WIRING IN

      BASIS Digital Multimeter
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                        (C) Mr.Linker '98


  If you have a digital multimeter
with audible indication, it without a special
Labor can be turned into a hidden network finder radio 
transmission or posting. But this would require the proposed 
attachment. 

  Scheme prefix to a digital multimeter to find the hidden 
power and radioprovodki shown in Fig. Its basis is the 
transistor VT1 with isolated gate. Shielded wires to

connects to the input jack device.

To be able to adjust the sensitivity of the seeker, the 
transistor is selected to a small initial current flow. At the 
same time initial resistance of the channel can be set to feed 
his gate with engine trim resistor R2 opens voltage. To protect 
the gate transistor from the powerful pickups and charges

static set
diodes VD1, VD2.

  Device works well. After connecting the console to a 
multimeter displacement engine resistor R2 sought appearance of 
monochrome signal. Then gently move it in reverse

direction until the signal loss - in this position, the device 
will be provide maximum sensitivity.


  If we now lead finder along the wall
hidden wiring, the place of its location in the antenna will be 
induced WA1 AC voltage, the amplitude of which is enough to 
transistor began to open. Channel resistance

transistor will change in time with
AC voltage. When it becomes
equal to or less than 1 ohm, a multimeter
beep, but not monotonous, but as a low-frequency trills.


  Click to view <V> scheme, ss +4
(Not leaving the show) - to record
schema to disk, edit, or break - to exit the viewer.


                        Radio No.5 '98

                        (C) Yu Prokoptsov

                        (C) Mr. Linker

                        12. 12. 1998