A light source, for example a light emitting diode, can emit light and have an associated optical axis. The second MOS transistor is in a differential connection with a gain control MOS transistor, which has its gate supplied with an AGC control voltage, and it is arranged that the device area ratio of the second MOS transistor to the gain control MOS transistor is one to N. The top and bottom trays each have a tab extending therefrom. One of the available frequency sequences includes increasing frequency pulsing.