Circuit

Lie detector

Contacts B1 and B2 (can be used thimbles of embroidery) should be connected to fingers of any hand. After  switching on the device with S1, you must wait 5-20 seconds before the end of the transitional process and both LEDs will turn off. The investigative must sit comfortably with stretched out hand (like in a blood pressure measurement), relaxed. For better effect, sensors B1 and B2 must be wet (accuracy is improved then). After each question it is necessary to give 2-5 seconds pauses for the investigative (until both LEDs will turn off). If the device goes on from any questions, or just itself, then you need to reduce the sensitivity with R10. You can use the device as a "detector of anger". Accuracy of the instrument is 70 - 90%. The results will be better if the investigative will not see what the indicator displays. Correct assembly of device does not require any tuning.

U1 is Russian chip K157УД2.
Datasheet for 2N3906.
Datasheet for 2N2712.
Datasheet for BZX79-C4V7.

Simple "bug"

Using this very simple schematic, You can spy someone :). Just place this little device somewhere that nobody couldn't see it and use Your FM radio receiver to listen what people are talking about. L1 and L2 - are air inductors (it means, they have no core inside the wire). L1 and L2 are in diameter of 2.5 mm. For FM operation at 65-108 MHz L1 and L2 have around 15 turns of wire in diameter of 0.3 mm. See the picture in the right.

Datasheet for BF970.

 Simple "bug" 2

This is another one simple circuit of bug. L1 and L2 - are air inductors (look at the first schematic of bug and it's description). L1 and L2 are in diameter of 2.5 mm. L1 and L2 have around 17 turns of wire in diameter of 0.5 mm. This circuit really works and it's sensitivity is pretty good, as for so simple circuit.

Datasheet for BF970.

 Circuit in .pdf format.

This circuit is more complex. Also this works from supply of 220V. T1 is built on ferrite ring 12 x 7 x 3, witch permittivity is 600 "12" - ring's outside diameter, "7" ring's inside diameter, "3" - ring's thickness. First winding has 100 turns of wire in diameter of 0,1 mm. Second winding has 20 turns of wire in diameter of 0,15 - 0,3 mm. T1 should be well insulated. Combine comfort with a lowered voltage of 30 V, connected to point A (not combine into a network device). The verification of stabilizing work VT2 short circuit in a housing base and help set the R10 ()

R10 (or oscilloscope dažnumačiu) U work 95 kHz. Measured on the R2. C2 help to determine the least distorted sinusoidal VT1 you on the manifold. Then remove the jumper from the database and make sure VT2 modulation bugs and work performance.

Datasheet for CD4011.

Datasheet for 2N2712.