This item was already assembled and tested, ready to use.

It requires center tap 18VAC AC-AC transformer to power the board. (The transformer is not included in the package ). User can select output voltage by selector switch +-3VDC, +-6VDC,+-9VDC,+-12VDC,+-15V and +-18VDC

It is suitable for the circuit which has op-amp, as you know that op-amp requires both positive and negative voltage to be the power

PCB size : 7.1cm x 12.0cm / comes with the schematic diagram

Below image shows how to connect the board with center tap transformer