The Model CS580 Voltage Controlled Current Source creates new capabilities for researchers needing an ultra-low noise current source in a flexible, easy to use instrument. The CS580 is a natural companion with sensitive AC instruments such as lock-in amplifiers, providing an easy way of generating precision current directly from an AC or DC control voltage. The instrument sources and sinks current and has an adjustable compliance voltage of up to ±50 V, giving full "four-quadrant" performance. The CS580 is a welcome addition to any research lab studying semiconductors and transport phenomena, superconductivity, and nanotechnology, to name just a few.