Voltage stabilizer

This stabilizer is very simple, but has very high parameters and consequently is suitable for a food of the most various equipment. At very good profitability - the current consumed by it in the absence of loading is not exceeded by 25 mkA-it provides a loading current to 0,5 A. Factor of stabilization - about 500, target resistance-0,07 Ohm. Distinctive feature of the stabilizer application in a regulating element of the powerful field transistor and work of an operating element in a mode of microcurrents. For the purpose of profitability increase by a source of exemplary tension obratnosmeshchenny emitterny transition of the VT3 transistor serves. High entrance resistance of the field transistor and big resistance of the R1 resistor cause big factor of strengthening of the managing director of an element, so and high factor of stabilization. The stabilizer is not afraid of short circuit of a target chain as in this case a current via the VT2 transistor, so and a current of loading will be limited to an initial current of a drain of the field transistor. Other important advantage is that at increase in temperature of the case of the regulating transistor the steepness of the characteristic and an initial current of a drain decrease, thanks to what in a mode of an overload of overheating of the regulating transistor with usual for the bipolar transistor avalanche uncontrollable increase in its current not присходит. The choice of the field VT2 transistor defines the greatest possible current of loading. Start of the stabilizer occurs automatically. At the moment of inclusion the VT1 transistor will be closed, therefore entrance tension will arrive on a zptvor of the field transistor, as provides reliable start of the stabilizer. Admissible tension a drain source of the field transistor equally 20 In, and for its normal work is necessary tension 2. . 3 In therefore the maximum target tension of this stabilizer can be 15... 17 Century. The minimum tension of stabilization is defined by tension of an otsechka of the field transistor and equally about 5... 7 V.Dlya of increase in a target current it is possible to use parallel turning on of two-three field transistors. In this case transistors should be picked up with close parameters. In order to avoid non-uniform distribution to them it is necessary for disseminated capacity to turn on the resistor in a chain of a source of each of them resistance 1... 2 Ohm. For improvement of quality of day off and stability of the stabilizer at work with loading of various character condensers C1, C2 are provided. In the stabilizer instead of КП903А it is possible to apply КП903Б, КП903В. It is necessary to establish regulating transistor on a heat-conducting path. It is possible to replace the Kt3102b transistor on КТ3102В - КТ3102Е, КТ342Б, КТ342В; instead of КТ315А any of Kt315b-KT315Zh will approach. At a loading current no more than 50 mA in a regulating element can be used КП305Г. At adjustment select the VT3 transistor with demanded tension of stabilization. It is possible to replace it with a usual stabilitron and to pick up the R2 resistor from a condition of providing rated current through a stabilitron. Profitability of the stabilizer thus the final will worsen.