We find this circuit in a Radio Electronics of July 1984. It consists of the traditional version of 1 A source, with the positive and negative regulators 7812 and 7912. Transformer can have 12 or 15 V of secondary and integrated circuits must be equipped of heatsinks. With the use of other regulators such as the 7806, 7808 or 7815 we can obtain other voltages, always remembering that the secondary of the transformer must have at least 2 V more than the output in the case of voltages below 12 V. Be careful that the terminal of the middle in the 7912 is not the ground.
