One of the most traditional voltage regulator circuits, quite old, but still in frequent use even in equipment manufactured today, is the voltage regulator “723”. If the reader needs a good-regulated power source for the bench, the circuit with the 723 is a good suggestion. This integrated circuit has a series of features that, with some external components, allows the elaboration of efficient power supplies in a wide range of currents and voltages. In the figure we have a typical high current power supply using this integrated circuit as a base. The characteristics of this power supply are:
• Adjustable output voltage between 2 and 15 V
• Maximum output current 1.2 A
As we can see, the transistor 2N3055, which must be equipped with a heat sink, controls the main current, the voltage being supplied as a reference by the integrated circuit 723. The secondary of the transformer must supply a voltage of 15 + 15 V with 1, 2 A and primary according to the power grid. For filtering, capacitor C1 must have a working voltage of at least 25 V.
