DC Power supplies

Power supply construction
A significant part of devices requires to be supplied with direct current (voltage). In such cases DC power supplies are used. The power supplies usually consist of a network transformer, rectifying system and filter (depending on required coefficient of output voltage pulsation).

Functional diagram of DC power supplies
Description: Sieć – Network, Transformator – Transformer, Prostownik – Rectifier, Filtr - Filter

In the system of direct voltage (current) power supply transformer separates galvanically the supplied devices from network and supplies the rectifying system with voltage of appropriate values. These transformers have greater power (in relation to their dimensions) and absorb more current from network in comparison to ordinary transformers. At the same power returned to the load they have greater dimensions and absorb current of higher intensity.

Rectifying system converts the alternating voltage (current) into pulsating rectified voltage (current) with the constant component different from zero. This system uses semiconducting elements (diodes or thyristors), which are conduct the current unidirectionally.
The rectifying system is characterized by the number of pulses. It determines the number of non-smoothed pulses in the run of rectified voltage falling on one period of alternating supply voltage.
Therefore the rectifiers are divided into: 1; 2; 3; 6; 12; 24 - pulse.

The filter’s task is to limit the pulsation so that to receive an appropriate value of direct voltage and current in the receiver. In stabilized power supplies a stabilizer of direct voltage or current may be installed between the filter and receiver.