Simple finder for hidden wiring

For the detection of concealed wiring, find broken wire in the wiring or the cable, detecting a blown bulb in electrovalence in most cases, it is simplest the device, consisting of a field-effect transistor, headset and one to three batteries (Fig. 1). The principle of operation of the device based on the property channel field-effect transistor to change its resistance under the influence of crosstalk on the output of the gate. Transistor VT1-KP103, K with any letter index (at last finding of the body are joined with the output of the gate). Phone BF1 - high resistance, the resistance of 1600 2200... Ohm. The polarity of the battery GB1 plays no role.

When you search for hidden wiring the body of the transistor drive along the wall and at the maximum sound volume at 50 Hz (if it is electric) or the radio (broadcasting network) determine the location of wiring.

Fig. 1. A schematic diagram of a simple finder

Place of wire breakage in unshielded cable (for example, the power cord any electrical or radio device), a burned out lamp electrovalency find so. All wires, including and tattered ground, the other end broken wire connects through resistor 1...2 MW slip ring wire the mains, and since the resistor to move the transistor along the cable (garland) out of sound - this is the location of the broken wire or faulty lamp.

The indicator can serve not only as the head-phone, but the ohmmeter (pictured dashed lines) or avometr included in this mode of operation. Source power GB1 and phone BF1 in this case not needed.

Author: V. Ognev, Perm; Publication: www.cxem.net