GenRad 1621 Capacitance Bridge from IET

GenRad 1621 Capacitance Bridge from IET

The IET GenRad 1621 apacitance Bridge measurement system is a fully self-contained system, capable of taking capacitance measurements in steps as small as 0.1 aF (10-7 pF) and conductivity measurements in steps as small as 100 aU (10-7 µU, equal to a shunt resistance of 1010MΩ). The measurements are 3-wire, with a 2- or 3-wire connection, and is also provided for connecting an external standard for comparison measurements.

Such capabilities and precision are usually associated with a limited frequency range and complex operation. However, the 1621 avoids these problems. Small performance reductions take place from 10 Hz to 10 kHz and operation up to 100 kHz is possible. Balance is achieved by in-line readout switches – easy to adjust and correctly read. All figures of capacity and conductivity, as well as relevant multipliers, are also made available by BCD coded contact closures, which can be used by printers or data equipment for rear connections.

The GenRad 1621 capacitance measurement system is a combination of three integrated instruments: a precision ratio-arm bridge, a very stable oscillator and an extremely sensitive detector. Most of the bridge’s internal standards are enclosed in an insulated housing to reduce the effects of ambient temperature; unused standards are disconnected to reduce shunt capacity at the detector input. The oscillator provides up to 125V or 5A: sufficient signal to be detected, even with an unbalance of only part 108 of 10 pF. The detector contains three meters to help you speed up the balance: one display shows the size and the other two displays simultaneously show the in phase and quadrature components of each unbalance.