428-PROG型可编程电流放大器应用指南

428-PROG型可编程电流放大器应用指南
How fast can I make measurements with a Picoammeter?
Introduction

This document compares the response times of the model 428 current amplifier to the model 6485 and
6487 picoammeters.

Many sensitive instrument products such as picoammeters or electrometers provide an analog output that
can be monitored with a data acquisition board or digitizing scope in order to maximize the speed of
measurement. These analog output signals from the instruments have rise time specifications which
indicate much faster measurements can be achieved from this analog output signal than with the
instrument’s front panel or over the IEEE-488 or RS-232 bus.

Methods

If a capacitor is put in series with a triangle wave, the resulting current will be a square wave. This
technique is used to deliv