Asymmetrical AC trigger simulation

A dimmer comprising:

• a) switching means having first and second terminals and a gate terminal;
• said first terminal connected to one side of a load;
• said second terminal connected to a source of AC voltage;
• said switching means operable to change from a state of high impedance to a state of low impedance upon the application of sufficient current to said gate terminal causing current to flow through said load;
• b) a conductor coupled between the other side of said load and said source of AC voltage;
• c) symmetrical trigger means having third and fourth terminals, said symmetrical trigger means fourth terminal coupled to said gate terminal of said switching means for preventing said switching means from changing state until sufficient voltage appears across said third and fourth terminals of said symmetrical trigger means;
• said symmetrical trigger means exhibiting negative impedance characteristic upon breakover and having similar breakover points during both positive and negative half cycles of a source of AC voltage;
• d) phase control means coupled between said one side of said load, said source of AC voltage and to an output terminal;
• and
• e) asymmetrical trigger means connected between said output terminal of said phase control means and said third terminal of said symmetrical trigger means, said symmetrical trigger means operable to compensate for charge depletion in said phase control means caused by said symmetrical trigger means;
• said asymmetrical trigger means effective to change state asymmetrically during each half cycle of said AC voltage.