Keithley 228A Programmable Current Source

Overview

The Keithley 228A is a precision programmable current source capable of sourcing or sinking up to 100 watts. With 4-quadrant operation, it functions as both a voltage or current supply and an active load without derating. The instrument features built-in voltage and current monitors, allowing continuous display and readback of output values via the IEEE-488 interface, eliminating the need for separate measurement instruments. The unit includes a rechargeable battery backup for memory retention.

Key Features

• 100-watt source or sink capacity
• 4-quadrant operation (bipolar voltage and current)
• Less than 1ms transient recovery without overshoot or oscillation
• Six output ranges for accurate regulation
• Built-in voltage and current monitors with front panel display
• Smooth range changes without disrupting the output
• Modulation input for DC to 600 Hz voltage programming
• Remote sensing for accurate voltage under high-current delivery
• IEEE-488 programmable interface (standard)
• Trigger IN/OUT for test synchronization
• Internal 100-point memory (non-volatile)
• Programmable dwell time and SRQ alerting
• Built-in diagnostics and error messages
• Rechargeable battery backup

Applications

• Component and device testing under various load conditions
• Power supply testing and rejection measurement
• Active load simulation
• Automated test system integration
• Variable load condition simulation