The invention relates to a control part for a starting circuit of a direct-current electric motor, comprising a variable resistor by means of which a starting voltage of the direct-current electric motor can be set, wherein the variable resistor can be controlled by means of a control voltage, wherein the control part comprises a frequency filter, the output signal of which forms the control voltage and is provided in such a manner that the variable resistor is activated with time delay. The invention further relates to a starting circuit for a direct-current electric motor comprising a control part according to the invention. The invention further relates to an adjustment device comprising a direct-current electric motor, and to a starting circuit comprising a control part according to the invention.