The Agilent HP1122A Power Supply is a fully transistorized, regulated power supply providing operating voltages for operation of oscilloscope probes. The supply is designed to provide all power requirements for simultaneous operation of up to four HP active probes. The power supply consists of a fused input circuit with selectable transformer primary windings for operation from a 115-volt or 230-volt power source. The input transformer drives two separate rectifier and regulator networks referenced to power ground. The power ground circuit is isolated from the chassis ground circuit to avoid ground loops between the supply and the connected probes.