Agilent HP 4262A

The 4262A LCR meter for component measurements uses a microprocessor to automate procedures, thus increasing the capabilities of the meter without incurring significantly greater costs. To measure the value of a passive component with this instrument, it is only necessary to select the measurement function and loss parameter - resistance (R), capacitance (C), or inductance (L), and dissipation factor (D) or quality factor (Q) - select the appropriate test frequency, and connect the component to the test terminals. The instrument automatically switches to the correct measurement range, selects the preferred circuit mode, and presents results on the 3½ digit displays in about 250 ms without any time-consuming balancing adjustments. The user, however, can have full manual control of the instrument at any time simply by pressing the appropriate front-panel pushbuttons.

Three test frequencies (120 Hz, 1 kHz, and 10 kHz) enable measurements of a wide range of component values.

As a safeguard against the possibility of unintentional missettings, the RANGE and CIRCUIT MODE functions automatically revert to AUTO whenever the L, C, or R function keys are pressed after manual modes have been in use.
Besides autoranging, self-triggering, and automatic selection of the appropriate circuit mode (series or parallel), the microprocessor brings several other capabilities to the instrument at little cost. Deviation measurement is one. When the ΔLCR key is pressed, the measurement value currently on display is stored, the display resets to zero, and the present measurement range is held. The result of the next measurement is then displayed as the difference between the new measurement value and the stored value.

For go/no-go measurements, a comparator option provides two pairs of thumbwheel switches on the front panel, one pair for LCR and one for DQ. Once high and low limits are established with these switches, a green light turns on when measured values are within the selected limits and a red light turns on when they are outside the limits.

Self test is another capability obtained with the microprocessor. At turn on, all LED indicators and all segments of the display digits light up momentarily to verify that all are functioning. Then, when the SELF TEST button is pressed while the input terminals are open (if the C measurement function is selected), or shorted (with the L or R measurement function), the instrument tests its digital section and the process amplifier and phase detector/integrator in the analog section, through five ranges. If all goes well, the word PASS appears in the LCR window and the user can be assured that the instrument is functioning correctly.

When the new instrument is equipped with the HP-IB option, the meter may be interfaced to a printer for logging measurement results, or to a desktop computer or other instruments for programmed measurements and statistical analyses of measurement results. All functions except DC BIAS are programmable through the HP-IB interface.

• Measurement frequencies: 120 Hz, 1 kHz, 10 kHz
• Parameter measurements
  • C - D or Q (1/D)
  • L - D or Q (1/D)
  • R (ESR)
• C ranges
  • At 120 Hz: 1000 pF to 10 mF
  • At 1 kHz: 100 pF to 1000 µF
  • At 10 kHz: 10 pF to 100 µF
• L ranges
  • At 120 Hz: 1000 µH to 1000 H
  • At 1 kHz: 100 µH to 100 H
  • At 10 kHz: 10 µH to 10 H
• D ranges for both C - D, C - Q and L - D, L - Q measurements: 0.001 ~ 19.9 (two ranges)
• Q ranges for both C - D, C - Q and L - D, L - Q measurements: 0.05 ~ 1000 (four ranges)
• R/ESR ranges: 1000 mΩ to 10 MΩ
• Deviation measurement: The difference between the referenced value and subsequent results in counts from -999 to 1999
• Measurement circuit modes: Auto, Parallel, Series
• Range modes
  • LCR - Auto, Manual (up-down)
  • DQ - Auto, Manual (step)
• Test signal levels
  • Normal level: 1 Vrms
  • Low level: 50 mVrms (parallel capacitance mode only)
• Offset adjustment for stray capacitance and residual inductance
  • C: up to 10 pF
  • L: up to 1 µH
• Trigger: Internal, External, Manual
• DC Bias
  • Internal: 1.5 V, 2.2 V, 6 V
  • External: Maximum +40 V
• Warmup time: 15 minutes