Sometimes, in our applications we must control loads at different voltages with respect to the control circuit. In this project we will develop an interface that allows us to control loads at 220 Volts in alternating circuits that operate at a lower voltage eg TTL circuits (circuits fed at 5 volts continuously). This interface can be used, for example, to control the light of a house, to control appliances, provided they do not exceed 500 watts.

Figure 1: Image of the 220V load controller.


The project outline is as follows and is based on a BT137 triac. The capacitors and the inductor have the function of eliminating noise in the system. This system is very versatile since it has been adapted both for use with computer or with microcontrollers.

Figure 2: Schematic of the 220V load controller.

The photos of the mounted system are as follows:

Figure 3: Top view of 220V load controller.


Figure 4: Bottom view of the 220V load controller.