| 摘要 |
<p>The arrangement contains a power shunt which is followed by a first amplifier circuit and can be used for processing the output current of an inductive current transformer having a wide dynamic range. In order to provide high-precision conversion with smaller currents, the power shunt is connected in series with a precision shunt which is connected in parallel with an overvoltage protection circuit which contains a switchable semiconductor rectifier and a control circuit which has the effect that the rectifier changes to a conductive state if the voltage at the precision shunt reaches a limit value. The control circuit contains a symmetric voltage limiting element which is constructed as a pair of limiting diodes or as a fullwave rectifier, the output of which is connected to a reference diode. In order to check the switching state of the overvoltage protection circuit, the series circuit consisting of the power shunt and the precision shunt is connected in parallel with a series circuit consisting of a first bridge resistor and a second bridge resistor which, together with the shunts, forms a balanced bridge circuit if the overvoltage protection circuit is inhibited, which bridge circuit is monitored by a window discriminator.</p> |
