Little boxes, little boxes.

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.

Rope light driversThe 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.

MOC3020 for mini trees.


The low voltage A/C circuits such as those used by
the mini Christmas trees also use triacs but they
are lower current devices typically 2A.



MOC3020 with bridge rectifiers


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.










Computer Control,
     Opto-isolators & RCD's

LED Hoops

Opto-isolator Boxes

Moving Messages

Baked Beans & Bulbs