Option of the adjustable stabilizer

And. ЗАВРИЧКО, Novoshakhtinsk
In article is described by the Rostov Region a voltage stabilizer at which power failure on the regulating transistor is minimum and the capacity consumed by the stabilizer is respectively reduced. Its application is especially useful for a food of radio-electronic equipment from galvanic cells and accumulators.
Almost any electronic device demands the stabilized power supply. Stabilizers are easy for constructing on well-known chips of the KR142EN series or discrete elements. But for successful operation of such stabilizers it is necessary, that power failure, i.e. value, on which brought supply voltage exceeds stabilized, there would be not less than 2... 3 V.Eto lead to a problem of dispersion of big capacity on the regulating transistor as in this case to it it is necessary "reserved from above" in some volt.
the Offered stabilizer keeps the properties at tension between a collector and the emitter of the regulating transistor, equal to tension of saturation (0,1... 0,5 In depending on a loading current).
Main technical characteristics: maximum current of loading-2 And; the maximum entrance tension - 30 In; an interval of target tension - 3... 25 In; factor of stabilization - 150.
Is the compensatory stabilizer with consistently switched on regulating VT1 transistor (see the circuit). On OU DA2 the comparator is accurate. Exemplary tension is created by a source of a stable current on the field VT2 transistor and a stabilitron of VD2 and moves on inverting входОУ. On not inverting entrance tension from a divider R3R4 proportional to day off arrives. OU compares this tension, and on its exit there is a necessary operating signal which arrives on the chip of DA1 containing four identical MOP-tranzistora with the induced channel of R type. Each transistor has parameters same, as at the discrete transistor of the KP304 series: resistance abroach — no more than 100 Ohm. a characteristic steepness - about 4 мА / Century All transistors of a chip connect br in parallel so that one transistor working as the istokovy repeater turns out as though. It is made for increase in an admissible current of a source of such transistor which can reach 80 мА. The steepness to 16 мА / Century "increases also Compound" MOP-tranzistor, having small resistance of the channel, effectively operates the regulating VT1 transistor. It is visible that the VT1 emitter potential always will be above base potential, it reaches operation of the stabilizer even at very small tension between the emitter and a collector (tension of saturation). the R1 Resistor limits to br the maximum current of transistors of a chip of DA1, its value should not exceed 80 мА. The R2 resistor and the VD1 diode are necessary for stabilizer start at food inclusion. Then these elements practically do not influence operation of the device. The variable R3 resistor establish necessary target tension. Its bottom limit is equal to tension of stabilization of a stabilitron of VD2 (for КС133А it is approximately equal 3,3 In), and top it is possible to determine by U formula = 3,3 • R3/R4.
At entrance tension no more than 25 In in the stabilizer it is possible to use chip К547КП1Б, and less than 15 In - К547КП1В. The VT1 transistor - any structure of R - p-R with an admissible current of a collector more than 3 And and admissible tension a collector emitter not less than 35 In, for example, Kt816b-KT816G, Kt818b-KT818G. On a place of VT2 transistors of series КПЗОЗ or КП307 are applicable. Instead of OU K140ud1208 will approach К140УД6 or К140УД7; in this case exclude the R5 resistor. The VD1 diode - any silicon low-power.
the Stabilizer assembled from serviceable details and without mistakes, does not need adjustment. Radio No. 6, 1999г./>/>/>/>/>/>/>!>