WIRE TAP

Description:

This wireless bug works on the principle of inductance. The phone wires are contacted to a magnetic coil connected to the circuit. This causes the audio signal on the line to induct into the coil. The induced signal is then amplified 200 times by an LM381 on the circuit in order to be made audible on a small set of headphones.

Application:

Since this bug requires a 36 volt power supply, it is not very portable. It can, however, be used very effectively if concealed in a back pack. All you need to do is lean against the building where the phone wires come in and your set. Just by wedging the coil between the phone wire and your pack you have initiated a live wire tap without even striping the wire.

Parts List:

Telephone pickup coil. (Radio Shack part) LM 381. (Obsolete, Looking for replacement) Resisters: 200 ohm, 2k, 47k, 100k, 100k, 1.2M Electrolitic Capacitors: 1uf Ceramic disk capacitors: .001uf, .003uf , 22uf

Reference:(note: you will need Adobe Acrobat Reader to view the scematic)

LM381 Schematic (Note: For circuit Schematic See "Magnetic phono preamp" in the reccommended circuits section)

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