To leave the oven unchanged, a controlled on/off power outlet is necessary.

A case from a dead PC power supply is used as an enclosure for the high voltage side of the controller. This is very convenient because it already has power sockets, fan and ventilation holes. The electronics from the old PC supply was removed and replaced with a smaller Mean Well PT-45B power source, a 220V AC to +5, +12 and -12V DC. This will power all the electronics.

The AC line is switched on/off by a BT139-600E triac, placed on a small radiator. The radiator size is big enough for a case with a running fan. For a galvanic isolation between the 220 AC line and the rest of the electronics parts, the power triac is driven by a small optotriac, MOC 3063. This particular model of optotriac have a zero-cross detection circuit included, so it will switch on the power only when the AC line sinusoid is close to zero. This is very good for the AC line power factor. The schematic for the power side is classic was extracted from the optotriac's datasheet.

It was tested by applying 12V DC to the input, and it was able to switch the 1400W oven and keep it on with no problem.

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