Circuit arrangement for current measurement in a conductor (L) carrying a current (I), wherein a
current transformer (CT) is configured to generate an input
voltage (U) from the current (I) in the conductor (L), which is supplied to the input (B1, B2) of a
diode bridge circuit (B), and a first output (B3) of the
diode bridge circuit (B) is located at the junction of two identical first electrodes (E1, E2) of the diodes (D1, D2) of the
diode bridge circuit (B), wherein a measuring
resistor (R) for current measurement is inserted between the two identical second electrodes (E3, E4) of the diodes (D3, D4) of the
diode bridge circuit (B), a second output (B4) of the
diode bridge circuit (B) is located at the junction of one of the diodes (D3, D4) with the second electrodes (E3, E4) and the measuring
resistor (R), and a extended bridge junction (B5) at the connection of the other diodes (D3, D4) with the second electrodes (E3,E4) and the measuring
resistor (R), and that diode (D4) of the
diode bridge circuit (B), which is located at the second output (B4), is formed by the source-drain diode of a first self-blocking field-effect
transistor (T1), and that diode (D3) of the diode bridge circuit (B), which is located at the extended bridge node (B5), is formed by the source-drain diode of a second self-blocking field-effect
transistor (T2), and a control device (CU) is provided to drive the gate (G1) of the first field-effect
transistor (T1) and the gate (G2) of the second field-effect transistor (T2) by means of the same control
voltage, and a measuring device (MU) is provided to measure a measuring
voltage across the measuring resistor (R), which is proportional to the current (I) in the conductor (L).