| 摘要 |
PCT No. PCT/GB92/02148 Sec. 371 Date May 19, 1994 Sec. 102(e) Date May 19, 1994 PCT Filed Nov. 20, 1992 PCT Pub. No. WO93/10463 PCT Pub. Date May 27, 1993.A method of sensing the rms value of a phase chopped sinusoidal electrical waveform including combining an input signal representative of the waveform with an auxiliary signal in a combining circuit which produces a combining circuit output equal to whichever is the greater of the auxiliary signal and the modulus of the input signal, and averaging the combining circuit output over at least one half cycle of the waveform. The resulting output signal level is representative of the sensed rms value. By making the auxiliary signal equal to the product of a predetermined factor multiplied by a desired value of the output signal level, a feedback signal is produced to allow control of the rms voltage delivered to a load such as a lighting circuit. |
