The wide capacitance range and high resolution of the GenRad 1412-BC decade capacitance box make it exceptionally useful in both laboratory and test shop. Owing to its fine adjustment of capacitance, it is a convenient variable capacitor to use with an Impedance Comparator. The polystyrene dielectric used in the decade steps is necessary for applications requiring low dielectric absorption and constancy of both capacitance and dissipation factor with frequency.
Mounted in a double-shield box, four decades of polystyrene capacitors and a variable air capacitor are used in the GenRad 1412-BC decade capacitance box. The double shielding provides 2-terminal and 3-terminal capacitances that are the same except for the capacitance between the terminals. The variable air capacitor with a linear ΔC of 100 pF and a resolution of better than 1 pF provides continuous adjustment between the 100-pF steps of the smallest decade.
Features：
Verifi cation of calibration of LCR meters
Capacitance measurement functions
Verifi cation of calibration of multimeters
For calibrating instrumentation
50 pF to > 1 μF
Better than 1 pF resolution
Accuracy of ± (0.5% + 5 pF)
Low loss, leakage, dielectric absorption
Capacitance: 50 pF to 1.11115 μF in steps of 100 pF with a 0 to 100 pF variable air capacitor providing continuous adjustment with divisions of 1 pF. Capacitance for 2- and 3-terminal connections differ by about 1 pF (CHG in Figure 1) CLC is approximately 125 pF.
Minimum Capacitance: 50 pF with all controls set at zero.
Dielectric: Polystyrene for decade steps.
Accuracy: ±( 0.5% + 5 pF) at 1 kHz for total capacitance including 50 pF minimum for the 3-terminal connection.
Temperature Coeffi cient of Capacitance: -140 ppm/°C (nominal).
Frequency Characteristics: DC Cap/ 1 kHz Cap < 1.001. At higher frequencies the increase is approximately ΔC/C = (ƒf /ƒf r )². The resonant frequency, ƒf r, varies from over 400 kHz for a capacitance of 1 μF to 27 MHz for a capacitance of 150 pF when connections are made to the front terminals. ƒf r is about 300 kHz and 70 MHz for rear connections and the same capacitance.
Max Operating Temperature: 65°C.
Dielectric Absorption: (Voltage Recovery): 0.1% max.
Dissipation Factor: 150 to 1000 pF, 0.001 max, at 1 kHz; over 1000 pF, 0.0002 max, at 1 kHz.
Insulation Resistance: 1012 Ω min.
Max Voltage: 500V peak, up to 35 kHz.
Terminals: Four bindings posts with grounding link are provided on the front panel. Two of the binding posts are connected to the case and located for convenient use with patch cords in 3-terminal applications. Access is also provided to rear terminals for relay-rack application.
Mechanical: Lab-bench cabinet; brackets provided for rack mount.
Dimensions: 0.89 cm H x 43.9 cm W x 15.3 cm D (3.5" x 17.25" x 3.5")
Weight: 3.9 kg (8.5 lb.) net, 4.6 kg (10 lb.) shipping.
