The proposed project aims at getting integral cycle switching for controlling AC power in linear loads like heaters used in electric furnace. Integral cycle switching is basically removing whole cycle or portions of cycles from an AC signal. This is achieved by using microcontroller of 8051 family programmed in assembly/C language such that whenever the signal is applied on the load, the actual time-average voltage at the load should be proportionately lower than the whole signal.
A comparator is used for zero crossing detection, fed to microcontroller as an interrupt. Microcontroller thus produces output as per interrupt received and generates triggering pulses. These pulses can then drive opto-isolators in triggering the TRIAC . Thus integral cycle is achieved as per the input switches interfaced to microcontroller. A lamp is used instead of motor to verify the output.