Various embodiments include a dimmer for controlling the power consumption of a connectable load. The dimmer includes: two parallel-connected, electrically isolated dimmer channels with control devices; a main control device for the channels; a communication link from the main control device to the channel control devices; and a communication link transmitting information from a first dimmer channel to a second dimmer channel. At least one of the two dimmer channels comprises a measurement device generating information about behavior of the electricity at a location in the measurement dimmer channel. The communication link transmits that information. Starting from the measurement dimmer channel, a channel communication link leads in each case from one dimmer channel to the next dimmer channel. The dimmer determines whether respective times of respective zero crossings of a sinusoidal AC voltage applied to the respective dimmer channel are substantially synchronous.