What are the differences between an electrometer, pico-ammeter and current amplifier?
Product(s):Electrometer: 6514,6517A,617,614, 6512,602,600B
Current Amplifier: 428-PROG, 428-MAN
Question: What are the differences between an electrometer, pico-ammeter and current amplifier?
Pico-ammeters are similar to Electrometer design for current measurement.
However, Electrometers are multi-function (measure Resistance and Charge) and offer more sensitive ranges for the current measurement function. Greater sensitivity provides better resolution and improved accuracy for extremely low current measurements. Electrometers are a better solution for more accurate measurements in the pA range.
As usual, speed is a trade off for this accuracy advantage. The preamp settling time, defined as 10% of final value, on electrometerâ€™s pA ranges is about 2.5 seconds. The preamp settling time on the nA ranges is similar to the picoammeterâ€™s nA range, in the mS.
If fast acquisition is a critical application requirement, a current amplifier may be the preferred solution. Unlike the pico-ammeters and electrometers, the Model 428 offers selectable filters to accommodate for noise / speed tolerances. The 10 â€“ 90% rise time can be configured as fast as 250uS on the 10 e 11 gain range with a 2pA rms noise level, or as slow as 300mS with 1.2fA rms noise level. Also different from the picoammeter and electrometer design, the current amplifier does not offer an internal A/D. The Model 428 has a 0-10volt analog output. This output can be used with data acquisition boards, oscilloscopes or waveform digitizers for low current measurement system or real time display.
This FAQ Applies to:
Product Series: Electrometers
FAQ ID 71766View all FAQs »