faskontroll

Faskontroll is a method for regulating alternating current power by controlling the phase angle at which power is delivered to the load during each half-cycle of the AC waveform. By delaying the triggering of a switching device, typically a thyristor or triac, the conductor conducts only part of each half-cycle, reducing the effective voltage and the average power delivered to the load.

In a typical faskontroll circuit, a control circuit advances the firing angle of the device from near the start of the half-cycle toward its end. As the triggering angle increases, the portion of the waveform that conducts becomes shorter, and the output voltage and power decrease accordingly. The technique relies on semiconductor switches that can withstand the line voltage and repetitive high-current pulses. Common implementations use silicon controlled rectifiers (SCRs) or triacs, often with a diac-based trigger network for simplicity.

Applications of faskontroll include light dimming, radiant heating elements, and small universal motor speed controls, where simple and cost-effective control is desirable. It is most efficient with resistive or lightly inductive loads; highly inductive loads can suffer torque ripple, unstable operation, and reduced control accuracy. The method introduces harmonics and electrical noise, can distort the current waveform, and may affect power quality and compliance with electrical standards. Safety considerations include proper insulation, isolation of control circuitry, and devices rated for the peak voltages and currents involved.

Historically, faskontroll became widespread in consumer electronics during the mid-20th century with the advent of SCR-based dimmers and has remained a fundamental technique in AC power control, despite alternatives such as switching and continuous control strategies.