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Adjustable kacher
As you know, Kutcher chooses the operation mode depending on the coil parameters and by others in the environment. But some tasks require a kacher with varying parameters. In addition, you may require galvanic isolation of the secondary winding Caceres coil with the rest of the circuit. Such kacher presented in the following figure:
Принципиальная схема регулируемого качера
As can be seen from the diagram, the coil L1 and the winding 2-2', which is responsible for feedback to the transistor VT1. It reduces the risks of breakdown and degradation of the transistor p-n junction, and allows you to isolate electrically the secondary winding of the coil 3-3' with the scheme. Collector coil in this case is activated in the same direction as the secondary; this inclusion is unusual for the standard scheme katscher. With proper adjustment of the scheme, such kacher consumes less energy for the same output parameters.
Another new element for katscher — turn ferrite rod in the coil L1, and it is a key regulatory element. Depending on how deep the ferrite bead inserted into coil, manifest certain properties of this scheme. If it captures only a small part of the inductor 1-1', we can obtain a fairly high voltage on the secondary winding, if the whole inductor, the high current in the lower part of the secondary. To control this current, we can, for example, enabling the load to rupture.
The first case can be improved by wrapping the coil with a non-magnetic screen. At certain distances between the screen and the secondary is possible to achieve wave resonance when the LC resonance coincides with the mode of the standing wave. On the oscilloscope it will manifest itself in the form of so-called "fish" — packs of sinusoidal oscillations with quite low for katscher frequency.
Setting the schema is. The resistor R1 is set to the middle position, and the capacitor C2 is at maximum. The indicator fields, for example such, control its intensity at the top of the coil. After power-up, this led should light. The resistor R1 is displayed in the lowest possible position according to the diagram, when the failure of oscillation is not yet happening. Depending on the tasks to achieve maximum performance with minimum C2 (gradually decreasing capacity). If, instead of the transistor 2SC2625 apply C4793, then trimming the capacitance C2 can not be removed — kacher independently out on the optimal mode and without it. In this case the 2nd output coil is connected to nowhere.
Need to pay special attention to the selection transistor VT1: depending on its parameters change the output parameters of the entire scheme. 2SC2625 develops more power, and C4793 — out for better working conditions. But kachery transistor 2SC5200 in this scheme showed rather weak results. Slightly worse, but quite acceptable, of domestic work from the series — КТ805. In any case, this transistor need to be installed on the radiator.
Coil L1 is done as usual katscher, but between the inductor and the secondary winding (between 1-1' and 3-3') on top of the 3-3' wrap-15-20 turns of the basic windings 2-2'. The wire it is necessary to choose how srednegorodskoy value of the thickness of the inductor and the thickness of the secondary. For example, the wire diameter of the inductor 5mm, and the diameter of the secondary is 0.5 mm, then the thickness of the base winding will be equal to the square root of the product of 5*0.5, i.e. — 1.6 mm. All the windings of that coil is wound in the same direction.