Picoammeter measures DC currents from 20fA to 20mA.
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Press Release Summary:
Model 6485 provides up to 1000 readings per second. It features 8 current measurement ranges and high speed autoranging. Its 5 1/2 digit resolution and voltage burden of less than 200µV on lower measurement ranges allow highly accurate measurements, even in circuits with low source voltages. Time-stamped 2500-reading data buffer provides min, max, and standard deviation statistics. Trigger Link interface allows synchronizing 2 or more instruments.Original Press Release:
Keithley Picoammeter Offers Femtoamp Measurements With Robustness, Speed, And Economy Near That Of A DMM
CLEVELAND-November 14, 2001-Keithley Instruments, Inc. (NYSE: KEI) today introduced its Model 6485 Picoammeter, the most cost-effective measurement solution available for DC currents in the range of 20fA to 20mA. The Model 6485 can make up to 1000 readings per second, and has the robustness and simplicity of a digital multimeter (DMM). This CE-marked instrument has eight current measurement ranges and high speed autoranging. The Model 6485's combination of affordable pricing and high performance means it can cost-effectively replace home-grown systems and higher priced alternatives, such as optical power meters.
Applications and Markets. There is a fundamental and growing need for low DC current measurements in many industries, such as the optoelectronics industry. Such measurements often require the sensitivity to measure currents of less than 100nA-something DMMs cannot deliver. Even at higher currents, a DMM's input voltage drop (voltage burden) can make accurate measurements impossible. Electrometers can measure low currents very accurately, but their versatility and extremely high precision circuitry increase their cost significantly. The Model 6485 combines the robustness, economy, ease of use, and speed of a DMM with current sensitivity near that of an electrometer. It expands on the capabilities of Keithley's earlier and most popular picoammeter, the Model 485.
Typical measurements include insulation resistance, leakage currents, photodiode and photomultiplier tube currents, SEM beam currents, sensor characterization, and I-V characterization of semiconductors and other components. It will also be of considerable interest to OEMs and system integrators who must include low-level current measurement functions in their test equipment.
Model 6485 Product Details. The Model 6485's 20fA sensitivity allows characterizing low current phenomena, while its 20mA range lets it measure currents high enough for 4-20mA sensor loops. Its 5-1/2-digit resolution and voltage burden of less than 200uV on lower measurement ranges allow highly accurate measurements, even in circuits with low source voltages. It offers ten times greater resolution on every range compared to its predecessor, the Model 485, and has a built-in Model 485 emulation mode that simplifies upgrading existing applications.
With a top speed of up to 1000 readings per second, the Model 6485 is the fastest picoammeter Keithley has ever made. A time-stamped 2500-reading data buffer provides minimum, maximum, and standard deviation statistics. It is designed for easy connection
io oiher inistruments and voltage sources with a built-in Trigger Link interface that allows synchronizing two or more instruments. The Trigger Link interface combines six independent selectable trigger lines on a single connector for simple, direct control over all instruments in a system. An IEEE-488 interface is included for controlling the instrument via the GPIB bus with a PC. It also has an RS-232 interface.
The Model 6485's rear panel connections allow the use of inexpensive, easy-to-use BNC cables. Its robust design and overload protection up to 220V let it withstand abusive overflows. A REL function permits making relative readings with respect to a baseline value; the LOG function displays the logarithm of the absolute value of the measured current. The Model 6485 can also calculate resistance by dividing an externally sourced voltage value by the measured current.
