| 摘要 |
<p>The signal lamp monitoring circuit in which a lamp is connected by a transformer with an a.c. power supply, includes a measuring resistance in one of the supply lines connected to a parallel threshold circuit with two sections, one for each line. These are used to compare a falling value with a lower threshold value. They are connected to a scanning circuit controlled in synchronism with the phase of the power supply. - Each threshold circuit section incorporates a loop with two series resistances and the diode section of an optical coupling device connected to each supply line. The output section of each optical coupling is connected to the scanning circuit.</p> |
