Picoammeters / Electrometers
Picoammeters and electrometers measure extremely low currents, in the femtoampere (10-¹⁵ A) to milliampere range, as well as ultra-low electrical charges, resistances and voltages. Their input impedance, often greater than 10¹⁴ Ω, minimises any disturbance to the circuit being measured. In R&D, they are used to characterise sensors, photodiodes, insulators and materials with very high resistivity. In metrology, they are used to check low-current measuring instruments and validate precision components. Their resolution can reach 0.1 fA with a thermal drift of less than 20 fA/°C. Some models incorporate functions for load integration, capacitance measurement and resistance up to 10¹⁶ Ω. USB, GPIB and LAN interfaces enable automated control and traceability of measurements to ISO 17025. Modern electrometers also provide leakage current compensation and temperature correction for long-term measurements.
Ultra-high sensitivity instruments for the electrical characterisation of materials and the metrology of very low currents.
6482-KEITHLEY
KEITHLEY
Dual-channel picoammeter/voltage source with IEEE-488 and RS-232 interfaces.
concrete questions about Picoamperemeters / Electrometers
01
What is the purpose of a picoammeter or electrometer?These instruments measure extremely low currents (pA, fA) and very small loads, often invisible to conventional multimeters. They are used to characterise sensitive components, analyse insulation leakage, measure the resistivity of materials or validate very low-current sensors.
02
What's the difference between a picoammeter and an electrometer?The picoammeter is optimised for measuring ultra-low currents. The more versatile electrometer measures currents, very high impedance voltages, extreme resistances and electrical loads. It offers enhanced stability in low-noise environments.
03
What are the main uses in laboratories and R&D?They are used to characterise photodiodes, test insulators, analyse PCB leaks, measure the conductivity of materials, study component drift or check the quality of dielectrics. They are essential for applications in physics, precision electronics and instrumentation.
04
What precautions need to be taken to obtain reliable measurements?The environment must be electrically stable, with shielding, suitable low-current cables (triax), and strict control of humidity and parasitic loads. Temperature variations, induced currents and surface contamination can distort measurements.
05
Is reconditioning appropriate for such sensitive instruments?Yes, under strict conditions: the device must pass full insulation, noise floor, linearity and thermal stability checks. Reconditioned electrometers continue to perform well if their low-current calibrations (pA/fA) and associated triax cables are checked. As their time stability is generally very good, they are suitable for most laboratory applications outside accredited metrology.
