From early summer to late autumn the recreation or entertainment of many summer residents and tourists interferes with nocturnal animals - clouds of flying insects, moths, etc. Against them fit "e" protection. which although not as effective. as pesticides, but more gentle to the environment! The following describes a trap for insects. Our trap was based on the "psychology of insects" that light bulb lures them to her. And here they are through a wire trying to get to the bulb.
Stretched wire mesh is connected to the high voltage. Separate wires are at a distance from each other, so that the breakdown strength of air was at the limit. Pass through the mesh insect decreases it, so through his body passes an electric current of a high voltage discharge, and the insect dies. The above already allows us to suspect that we are talking about such a device, where electronics - because of its extreme simplicity is a minor problem compared to the mechanical design.
Despite this, we first consider the electric circuit shown in Fig.1 and is offered in two versions. This scheme is divided into the following main components: - AC rejection filter (noise filter); - electronic control: - high-voltage transformer.
(click to enlarge)
Scheme (Fig.1) works as follows. The capacitor C2 is charged from the mains voltage through a diode rectifier D1 and a resistor R2 to the amplitude of the mains voltage (310 V). This voltage enters through the primary winding of the transformer T] at the anode of the thyristor Th,. On the Other branch (Rl, D2, C1) slowly charging the capacitor C1. When during the charging of C1 is achieved breakdown voltage dynistor Di (within 25...35 V), the capacitor C1 discharges through the control electrode of the thyristor Th and opens it. Through an open thyristor and the primary winding of T1 quickly discharges C2. Changing pulse current induces in the secondary winding T1 of the high voltage, the value of which can exceed 10 kV. After discharge of the capacitor, the thyristor is closed, and the process repeats. Allowable voltage elements shall be as specified in the scheme values. The most important problem is the production of high-voltage transformer.
You can use ready-made high-voltage winding, which is nothing more than a secondary winding of the transformer horizontal black and white TV (aka "millstones"). The transformer in some quiet time "grouchy". However, the accompanying sound effects work even useful since they indicate the presence of high voltage. for example when the lamp filament in the trap. Generally, silently working device could play a cruel joke on unsuspecting passers-by inadvertently draws near. Rejection filter at the input is a necessary companion of any controlled thyristor circuit. The device creates a radio and TV interference filter unit and gives you the ability to watch radio and television programs.
Wire "curtain"and mechanical design. The most critical component of our design is very precise manufacturing wire "curtains". To obtain it from any good insulating material (for example from textolite or Plexiglas plate of thickness 4 mm) cut out two discs with a diameter of 170 mm and two discs with a diameter of 150 mm Along the perimeter of each pair of disks in 10° cuts made jigsaw depth of 5 mm (36 pieces). Then disks are marked through 120° and the holes are drilled with a diameter of 5 mm. After that, the supporting brackets are made. In the pilot it was 3 brass rod with a length of 210 mm and a diameter of 5 mm, on some ends of which there was a thread length of 50 mm and the second length of 30 mm. Discs together so that two smaller were inside, and two large outside. On the ends of the threaded rods mounted wheels with small and large diameters of approximately 15 mm from each other.
It is advisable to slit the small and large disk to install so. so they do not fall on a single line, and were shifted to the middle of each relative to the other about 15 mm. the Bottom of the frame will be the drive in which are screwed the ends of the rods with a long thread, but with a shorter cover . If the frame is normally gathered. upper disc is removed and in their mid jigsaws saws hole for the filament lamp holder. The dimensions depend on the application of the lamp. I used lamp type "minion". You also need to take care of this mount holder (for example detachable top), so you can replace the bulb without disassembling the grid. For the grid used was a bare copper wire with a diameter of 0.45...0.5 mm. It should be immediately pre-stretch in the gap along the perimeter of the disc. If you use wire with enamel insulation works more will be added. Since it is necessary to remove the entire length of the insulation with sandpaper. After installing the inner and outer parts of the curtains are taken from the ends of the large and small disks and are connected to the ends of the high voltage winding. Finished design is attached to a suitable plastic box, in which the electronics.
Installation and operation
Form of payment must correspond to the shape and size of the plastic box. High voltage transformer is going well. From "extracted" from the TV core high-voltage transformer primary winding is removed, and in accordance with its size made a new coil. For a new primary winding is used winding wire diameter 0.8 mm. the Number of turns - 25. For the secondary winding suit any defect-free "millstones" to the black-and-white TV. For bandstop filter is best suited high-frequency ferrite cores with about 20 turns of winding wire diameter of 0.6...0.8 mm. After final installation of the electronics Board, connect the power cable, and wire curtain is connected to the "millstone".
After switching on the lamp lights up and the device is quiet "grunts", signaling the presence of high voltage. Through a double wire mesh spark does not slip. If you still skips, or the voltage is too high. or rows of wires are too close to each other. For fixed geometrical dimensions of "curtains" required voltage is set by adjusting the electronic circuit. The test ends test the spark with a screwdriver. Slide the screwdriver between the two rows of wires - now on both sides of the screwdriver should slip sparks. Large internal resistance of the transformer itself protects against dangerous amount of current during the formation of the discharge. But still strongly reminiscent of the observance of the rules associated with working with high voltage, as in manufacturing. and during operation.
Touch hands to the wire "cage" will be very unpleasant. Therefore, if posted, you must consider the fact that the device be used only in the dry season. or place it where it is impossible to accidentally touch.
Author: C. NAGYMATE, Translated by A. Belsky; Publication: N. Bolshakov, rf.atnn.ru