Power Supply Output Voltage Regulator by a Gyrator Circuit

Figure 1 

In most of the power supply circuit designs, after the rectification stage of the AC signal, large, heavy and expensive electrolytic capacitors are used to avoid the ripple voltage at the output. In this design, this large capacitors are replaced by an active power transistor (2N3055) gyrator circuitry which also does the same job greatly and less costly.

The principle of the gyrator circuit is it multiplies the capacitance value of the capacitor connected between the base and the emityer terminals by the static forward current gain, HFE of the transistor. Assume 2N3055 has an HFE of 50, then the value of 100uF capacitor is multiplied by 50 and results a capacitance value of 5000uF.

The circuit also provides a soft power-on since the voltage stabilisation and reaching the maximum value take a few hundred milliseconds.

The regulated and unregulated output voltage behaviour graph is given in the circuit page.

Read More:www.zen22142.zen.co.uk/Circuits/Power/gyrator.htm