Simple add-on for a single-rail supply
Â±2.5V to Â±15V output
R1,R2____________4K7 1/2W 1% or 2% Metal Oxide Resistors
C1,C4,C5_______100nF 63V Polyester Capacitors
C2,C3__________220ÂµF 25V Electrolytic Capacitors
Q1____________BD437 45V 4A NPN Transistor
Q2____________BD438 45V 4A PNP Transistor
IC1___________LM358 Low Power Dual Op-amp
Input and output connecting terminals etc.
This simple unit provides a dual-rail variable output ranging from Â±2.5V to Â±15Vdc with precise tracking of the positive and negative output voltages, still retaining the current limiting and short-proof capabilities of the “master” circuit.
As the purpose of such a dual-rail design is to supply experimental or under-repair circuits, the maximum current output delivered was deliberately kept to about 500 – 600mA per rail, thus avoiding the use of expensive power transistors and complex circuitry.
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