1621 Capacitance Bridge
1621 Capacitance Bridge represents the first major improvement in nearly a decade in ultra-precise laboratory capacitance intercomparisons and dielectric measurements.
Three integrated units: precision ratio-arm bridge, highly stable oscillator, and an extremely sensitive detector. Completely self-contained system
Capable of capacitance measurements in increments as small as 0.1 aF (10-7 pF) and conductance measurements in increments as small as 100 aS (10-10 µS; equivalent to a shunt
resistance of 1010 MΩ)

• Measurements are three terminal, with 2- or 3
  terminal connection, and provision is also made
  for the connection of an external standard for comparison measurements

• Little degradation of performance occurs from
  10 Hz to 10 kHz and operation to 100 kHz is
  possible

• Balances are achieved by in-line readout lever switches-easily adjusted and read correctly

• All digits of capacitance and conductance,
  as well as pertinent multipliers, are also provided
  by BCD-coded contact closures, available at
  rear-panel connectors for use by printers or
  data-processing equipment

Most of the bridge's internal standards are enclosed in an insulated housing to reduce the effects of ambient temperature changes; unused standards are disconnected to reduce shunt capacitance at the detector input.
Oscillator provides up to 125 V or 5 A for sufficient signal to be detected even with unbalances as small as one part in 108 of 10 pF.
Detector contains three meters to help you speed the balance: One displays the magnitude and the other two simultaneously display the in-phase and quadrature components of any unbalance.