| 摘要 |
<p>The power control circuit described functions to vary the duty cycle of the alternating current signal supplied to the load. The duty cycle is varied by periodically generating a first signal, each half cycle of the alternating current signal, that is proportional to the actual power supplied to the load as a function of the duty cycle and wave form of the alternating current signal. A comparator compares this first with an error signal to vary the duty cycle in accordance with the power demanded by the error signal. The first signal is derived by evaluating the integral of the square of the voltage over each half cycle of the alternating current signal.</p> |
