Keithley 6514 Programmable Electrometer

The Keithley 6514 Programmable Electrometer is a high-precision instrument for measuring DC current, DC voltage, charge, and resistance across nine orders of magnitude. With 6½-digit display resolution, input impedance exceeding 200 TΩ, and input bias current below 3 fA, it captures low-level signals without degradation. The instrument delivers up to 1200 readings per second and settles in milliseconds on most ranges, making it suitable for research, development, and quality control where measurement fidelity is critical.

– Technical Specifications

Measurement Functions: DC Current (100 aA to 21 mA), DC Voltage (2 mV to 200 V), Charge (10 fC to 20 µC), Resistance (2 kΩ to 200 GΩ)

Display & Resolution: 6½-digit vacuum fluorescent display with 5½-digit resolution

Input Characteristics: Input impedance >200 TΩ (parallel with 20 pF, guarded <2 pF). Input bias current <3 fA with 0.5 fA/°C temperature coefficient. Input voltage burden <20 µV on pA/nA/µA ranges; <100 µV on 200 pA/nA/µA ranges; <2 mV on 2 mA; <4 mV on 20 mA.

Noise Performance: <1 fA noise floor. Input bias current noise 55 dB across 50 Hz/60 Hz ±0.1%. Common Mode Rejection >120 dB at DC and line frequencies.

Speed & Settling: Up to 1200 readings/second (fast integration) or 17 readings/second (60 Hz line-cycle integration). Settling varies: 15 ms on 2 nA; 2–90 ms on resistance ranges (2 kΩ–200 MΩ); 1 s on gigaohm ranges; 2.5–3 s on pA ranges.

Filtering & Conditioning: Median and averaging digital filters (2–100 readings, selectable). User-selectable damping in current mode.

– Key Features

• Built-in constant current source for simplified resistance measurements
• 2 V analog output (10 kΩ impedance) with inverting capability in current/charge modes
• Preamp output for guarding in voltage mode or external feedback in other modes
• Median/averaging filters with user-defined reading count
• Guarded input configuration reduces parasitic capacitance to <2 pF

– Electrical Interfaces

• IEEE-488 (GPIB) via SCPI protocol (IEEE-488.2, SCPI-1996.0)
• Handler interface with start/end-of-test signaling and 3 category bits
• One trigger input and 4 digital outputs (500 mA sink capability)

– Typical Applications

Semiconductor characterization, electrostatics testing, photomultiplier measurements, surface leakage analysis, and environmental chamber monitoring.