running lights

7-76 elektor july/august 1980 82 The running light circuit described here is by no means the first (or the last) to be published by Elektor, but it is one of the more interesting. The circuit has no less than eight channels, each of which can be independently programmed. The maximum power " output per channel is determined by the specifications of the triacs used. As the lamps are switched on at the mains zero-crossing point, no inter- ference is generated, thereby elimin- ating the need for noise filters. Figure 1 shows the block diagram of the unit. Any eight bit code can be preset at the inputs of two shift registers by switches S1 . . . S8. A corresponding LED will light when a switch is closed to give an indication of the state of the switch and there- fore the eight bit code. This preset data is then entered into the shift registers by S9. The shift registers are bi-directional and the position of S10 determines whether the data is shifted left, right or remains static. Data...