The TRIAC is used in single phase AC load control, for example in heating, light and motor control. The circuit is relatively simple, but not its design and control.
As soon as the capacitor voltage gets larger than the on voltage of the DIAC, the TRIAC will start conducting. The value of trigger voltage of the diac can be set in the DIAC component.
Change R2 from 1k to lager values ,like 2k, 5k, 10k 22k, 68k to control the on time
The light dimmer is greatly simplified . However a snubber across the TRIAC is required to filter the voltage spikes.
For motor control, the TRIAC circuit is enhanced with more filter components. Change R3 from 1k to 68k to control the speed of the motor. This circuit is typically found in vacuum cleaners.
A softstarter is used in industrial motor control to reduce the size of the currents during start up of a three-phase induction machine. The simulation below sows the difference between a directly to the grid connected induction machine and one operating from a softstarter. Notice that the maximum current in the case of the softstarter is around 300 ampere, while for the directly to the grid connected machine a start-up current of around 1000 Ampere is flowing.
For single-phase and three-phase control, either a Triac or complete softstarter is used. Notice that the Diac component can be found under the section of components/circuit/semiconductor, while the triac has to be selected from components/library/semiconductor/triac.
Firing a Triac from a microcontroller can be done using an OptoTriac. Here the triac is fired using an AC triac that is triggered using a light emitting diode.
