Method of triggering at least one illuminating means, and triggering circuit for carrying out such method. On motor vehicles, the illuminating means are increasingly being formed by LEDs. Owing to the great possible operating voltages of the on-board network, such illuminants cause great power losses at high voltages. Besides, the networks aboard motor vehicles are often unstable. So that reliable operation will be possible with simple design layout, the illuminating means is operated in pulse mode when a certain current/voltage level is exceeded. The triggering circuit has a microcontroller, which is supplied with a part of the current/voltage signal supplied to the illuminating means. The microcontroller has an output to which the illuminating means is connected with interposition of a switch. In pulse mode, the ascent of the power loss is substantially reduced. Brightness fluctuations are regulated out. The triggering and the triggering circuit are advantageously employed for motor vehicle lamps.