POWER SUPPLY UNIT HAVING AN OFF -DELAY SWITCHING CIRCUIT

摘要

The circuit arrangement has a power supply unit (I, II, III), a mains switch (S1) and a switching element (Rl), for example a relay, that bridges a first switching contact (1) of the mains switch (S1). A load (L) is coupled to a control terminal (4) of the switching element (R1), so that when the control voltage (US) is turned off for the purpose of opening the switching element (R1), the load (L) is simultaneously turned off. The circuit arrangement contains a microprocessor (UP), in particular, which is supplied with an operating voltage (U1) by the power supply unit (I), and which is coupled to the control terminal (4) of the switching element (R1) for control of the switching element (R1). The load (L) is a fan, for example, which is switched off in a delayed manner when the circuit arrangement is switched off by means of the mains switch (S1).