Feature of this transistor compensation voltage (see picture) – used in the feedback field effect transistor VT3, which acts as a dynamic load for the transistor VT2. Because of this factor increases the voltage regulation: when the input voltage from 11 to 19 V output voltage varies within ± 60 mV. Rated output voltage using Zener type D814B is 9 V.
Rated load stabilizer – 0.1 A. The control transistor VT1 is mounted on the radiator in the form of an aluminum plate measuring 35×40 mm, and its static current transfer ratio of about 50. Conversely, the transistor can be used MP37A MP113A transistors, and as a replacement for zener D814B – D809. If it is necessary to obtain a value of output voltage, you must apply another type of zener with a corresponding voltage stabilization.
In the latter case may require selection of the resistor R1. When you replace the last one more field-effect transistor type KP102 (gate and source are connected to the zener, and runoff from the collector of the transistor VT1) rate stabilization device further increases.