In order to display the time as accurately as possible, the radio-controlled clock receives a transmitted time signal. This is used to readjust the internal quartz clock so that the correct time is displayed. There are time signal transmitters at various locations, for example near Frankfurt am Main, in Japan or in Switzerland. The signal reaches several thousand kilometres and is adapted to world time. The signal for transmitting the time is sent out continuously, but reception is often only hourly or daily. This serves to save energy, as wristwatches only have a certain battery life, depending on the movement, and this regularity is sufficient to correct any rate errors. If the signal is disturbed, the watch continues to run normally, but cannot readjust the time, so that rate errors can occur. In addition, a radio-controlled clock automatically adjusts to summer or winter time, so that it is not necessary to readjust the time individually. In addition to conventional quartz clocks, there are also radio-controlled solar clocks that run on light energy and are therefore continuously supplied with energy.
