| 摘要 |
<p>The method involves rectifying a half wave of electrical alternating voltage (Ue), and applying the voltage to an input of a comparator (V) over voltage dividers (Rx, Ry). The voltage is compared with a reference voltage (Uref) lying at another input of the comparator, such that a pulse-width modulated signal is produced. The pulse-width modulated signal is transmitted to a signal evaluation device i.e. microprocessor, over an opto-coupler. Level of the voltage is determined by the evaluation device based on a duty cycle of the pulse-width modulated signal and compared with a limit value. An independent claim is also included for a circuit for detecting and monitoring electrical alternating voltage.</p> |
