摘要 |
<p>The dc isolating circuit, for TDM transmission systems, avoids using an optoelectronic coupler and its associated relatively complex circuitry. The circuit includes one capacitor (1) a resistor (2) and an input trigger diode (3). The input trigger diode (3) is coupled in series with the primary winding of a transformer (4). This series combination is connected in parallel with the capacitor (1) charged over the resistor (2) from a 110V dc source. The trigger diode has bidirectional characteristics and can be eg a diac or antiparallel thyristors. The 110V applied to the input charges the capacitor. At a given point the capacitor voltage triggers the diode. The diode discharges the capacitor through the primary winding.</p> |