Keithley 428-PROG
Programmable Current Amplifier

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Product Overview

The Keithley 428-PROG Programmable Current Amplifier converts fast, small currents to a voltage, which can be easily digitized or displayed by an oscilloscope, waveform analyzer, or data acquisitionsystem. It uses a sophisticated "feedback current" circuit to achieve both fast rise times and sub-picoamp noise. The gain of the Keithley 428-PROG is adjustable in decade increments from 103V/A to 1011V/A, with selectable rise times from 2μs to 300ms.

Features and Specifications of the Keithley 428-PROG Programmable Current Amplifier include:

• Applications in research and device labs due to its cost-effective ability to amplify fast, low currents, incude:
  • Biochemistry Measurements:  Ion channel currents through cell walls and membranes
  • Beam Position Monitoring:  Used on electron storage rings and synchrotrons
  • Surface Science Studies:
    • Scanning Tunneling Electron Microscope system amplifier
    • Observation of secondary electron emission, as in X-ray and beam line currents
  • Laser and Light Measurements: 
    • Fast, sensitive amplifier for use with PMTs and photodiodes
    • Analysis of fast photoconductive materials
    • IR detector amplifier
  • Transient Phenomena:
    • Current DLTS studies
    • Breakdown in devices and dielectric materials
• Can be connected to an oscilloscope or waveform digitizer to display very low currents in real time
• Offers fast response at low current levels
• Nine current amplification ranges allow the greatest flexibility in making speed/noise tradeoffs
• Can be used with any of Keithley’s data acquisition boards to implement a very cost-effective, low current measurement system with wide bandwidth and fast response
• Incorporates a second order Bessel-function filter that minimizes noise without increasing rise time on high-gain ranges
• Input and output connections are made with BNC connectors:
  • INPUT HI is connected to a programmable ±5V supply
  • Permits suitable bias voltages to be applied to devices-under-test or current collectors
  • This eliminates the need for a separate bias supply
• Exterior design incorporates:
  • Front panel operation
  • Pushbutton controls have an LED to indicate if that function is activated
  • Display features three selectable intensities (bright, dim, and off) for use in light-sensitive environments
  • All setup values can be displayed from the front panel
• 2μs rise time
• 1.2fA rms noise
• Up to 10¹¹ V/A gain
• IEEE-488 interface