Abstract: A circuit arrangement for generating a pulsatory supply voltage for a load (1), such as a halogen incandescent lamp, from a source of direct voltage, in which a predetermined effective value of the supply voltage remains substantially constant in the case of a varying direct voltage. A switch (2) supplies the supply voltage from which a low-pass filter generates a mean value voltage. The mean value voltage is applied to a Schmitt trigger circuit (3) which controls the switch whose first switching threshold is constant and is derived from a reference voltage which is present at a first input of the Schmitt trigger circuit. A second switching threshold of the switch varies oppositely with respect to a decreasing direct voltage.