Smooth inclusion of loading of the integrated stabilizer
Integrated adjustable voltage stabilizers of the series KP142, КР1157, КР1168 and the similar foreign are widely applied in radio amateur practice. Using possibility of change of value of stabilized tension by means of hinged elements, it is possible to provide a smooth exit of such stabilizers to an operating mode. It appears very useful to decrease in overloads of the rectifier and the stabilizer or any reduction of hindrances (for example, clicks in the EXPERT) at the moment of equipment inclusion. the Standard circuit of the stabilizer is shown to p by
on fig. 1. The capacity of condensers C1 and С2 corresponds to standard inclusion of a chip. Target tension defines a resistive divider of R1R2. Elements of the additional knot providing smooth inclusion, are drawn with shaped lines.
of the Fig. 1. The standard circuit of the stabilizer
At turning on of the stabilizer on an exit of a chip appears tension. As the SZ condenser starts to be charged, the VT1 transistor will be open and during the initial moment target tension will not exceed 2,4 V.Po mere of a condenser charging the transistor is closed and tension on its collector increases. Therefore, target tension increases also. When the condenser will be charged, target tension will reach the established value. The transistor will completely be closed and will not render influence on operation of the stabilizer. After device shutdown the SZ condenser is quickly discharged via VD1 and VD2 diodes, a resistive divider of R1R2 and loading.
Time of increase of target tension depends first of all on capacity of the SZ condenser and resistance of the R4 resistor and to a lesser extent — from factor of transfer of a current of the transistor.
For comparison was measured by p time of increase of target tension of the stabilizer. At target tension 15 In, resistance of loading of 15 Ohm and capacities of condensers of filters of the rectifier and loading on 4700 мкФ without the specified completion is time made about 30 ms. And after introduction of additional knot — about 1,5... 2 pages to
Admissible tension of all condensers and the transistor should correspond to working tension in a concrete voltage stabilizer.
In this way can finish stabilizers and on the basis of other chips, only for the stabilizers which have been switched on in a minus chain, it is necessary to apply the transistor of other structure and to change polarity of turning on of condensers. Besides, such additional knots can be entered into the power unit with several target tension to provide a certain sequence of giving of feeding tension.
Author: И.НЕЧАЕВ, Kursk!>