Throughout all of the display the interface outputs are isolated electrically from the switched circuits by opto-isolators, irrespective of the switched circuits being 230 volts or a low voltage.
The boards are very simple in construction, being done on a piece of Veroboard or Stripboard as it is also known and uses the MOC3020 IC.
The rope lights that are used in the Merry Christmas & Happy New Year display are driven directly from the MOC3020 IC's as the rope lights only draw 70mA and the MOC3020 can handle 100mA.
The higher current 230v circuits have a triac connected to the output, typically a BTA08-600B. Various triacs can be used dependant on the voltage and current being switched, for the relatively low cost of triacs I have well over rated these by using 400volt 6A/8A types so that heat dissipation isn't a problem especially as I haven't used any heat sinks.
The low voltage A/C circuits such as those used by
The last version of the opto-isolator circuits is the one use to drive LED's,
it still uses the MOC3020 IC which switches A/C but has a bridge rectifier IC
connected to the output so as to drive the LED's direct.
One of the opto-isolator boards with the sockets in it's rain proof box. The sockets are mounted in square section waste water down pipe cut in half.
Opto-isolators & RCD's
Baked Beans & Bulbs