Agilent / Keysight 34939A 64-Channel Form A General Purpose Switch for 34980A

The Keysight 34939A is a 64-channel Form A general-purpose switch module that plugs into the Keysight 34980A Multifunction Switch/Measure Unit. It delivers high-density signal routing for automated test systems through 64 independent Single-Pole, Single-Throw (SPST) latching armature relays. The module handles switching currents to 1 A, carrying currents to 2 A, and maximum power of 60 W per channel at voltages up to 100 V AC/DC - ideal for cycling power to devices under test, controlling indicator lights, and actuating external relays or solenoids.

Technical Specifications

• Channel Count: 64 independent SPST relays, Form A configuration


• Switching Current: 1 A maximum


• Carrying Current: 2 A maximum


• Power Capacity: 60 W per channel


• Voltage Rating: 100 V AC/DC maximum


• Relay Type: Latching armature relays with integrated cycle counter


• Thermal Protection: Built-in temperature sensor; system interrupt triggered at approximately 70 °C


• Multi-Channel Operation: Simultaneous switching across multiple channels supported


• Connectors: Standard 78-pin D-sub connectors

Key Features

• Configurable power-fail state via jumper - selectable between open or maintained relay position


• Optional 34939T screw terminal block accessory supports wire gauge up to 20 AWG (18 AWG maximum)


• Relay cycle counter tracks switching operations for maintenance planning


• Temperature monitoring prevents thermal damage during extended operation

Typical Applications

• Power cycling for devices under test


• Indicator and status light control


• External relay and solenoid actuation


• General-purpose signal routing in automated test equipment


• Device actuation and digital output control

Compatibility & Integration Designed as a plug-in module for the 34980A mainframe. The 34980A supports up to 8 modules, enabling flexible configuration of specialized switching and measurement functions.