Adjustable bipolar power supply

In laboratory of the radio fan as a rule is the adjustable stabilized power unit. Having added to it a simple addon, it is possible to receive the bipolar power supply.

the Circuit of such addon is represented by font in drawing. It is calculated on work in common with the stabilizer having target tension of 12 volts and a current of load of 2 A.Pristavka is equipped by the amplifier of capacity on transistors that allowed to increase device efficiency at change of resistance of loading largely.

the Ratio of target tension of a source can be changed p within 0,6... 1,6 variable R2 resistor. At a ratio equal to 1, the maximum current of loading of each shoulder it is equal 2 And, at the extreme - values it should be reduced in 1,5... 2 times. The addon works like a voltage stabilizer with in parallel included regulating element.

the Operational A1 amplifier compares tension on an exit of a resistive divider of R1R2R3 to tension on "OBShch" conclusion. amplifier of capacity of V5, V6. The difference between this tension is minimized by corresponding change of tension of shift of the V3 transistor. The chain of V1V2R4 serves for initial installation of tension of shift of this transistor. If it is necessary to increase target tension of shoulders of an addon with 6 to 12 In, it is necessary to lift tension of its food to 24 In and to replace an operatsionnik on К1УТ401Б. Thus corresponding change (increase) in resistance of R4 and R5 resistors is required.