The Keysight 34908A is a 40-channel single-ended multiplexer module for the 34970A and 34972A Data Acquisition/Switch Units. It routes signals from multiple sources to test instruments using break-before-make relays optimized for common-low configurations. The module’s isolated low connection floats up to 300 V, enabling flexible test setups for battery characterization, component testing, and benchtop applications without earth-ground constraints.
Technical Specifications
• Channel Configuration: 40 single-ended, one-wire inputs
• Switching Architecture: Break-before-make relays; single-wire switching
• Scanning Speed: Up to 60 channels per second
• Module Low Isolation: Isolated from earth; capable of floating up to 300 V
• Supported Measurements: All two-wire internal measurements except current
• Built-in Reference: Thermocouple reference junction
• Signal Routing: Internal analog bus connects low-frequency multiplexers directly to internal DMM
– Key Features
• On-module screw-terminal connectors for direct wiring
• High-density channel count in compact form factor via surface mount construction
• Isolated floating low enables measurements above ground potential
• Integrated thermocouple reference eliminates external compensation circuits
• Break-before-make relay action prevents transient cross-connection during channel switching
– Operating Conditions
• Temperature: 0 °C to 55 °C
• Humidity: 20% to 80% at 40 °C or less (non-condensing)
• Altitude: Up to 2000 meters
• Installation Category: II
• Pollution Degree: 2
• Shipping Weight: 4 lb
– Compatibility & Integration
The 34908A plugs directly into Keysight 34970A or 34972A mainframes. Internal signal routing eliminates need for external cabling between the module and host unit’s analog measurement engine. Screw-terminal connections accept standard 22–16 AWG instrumentation wire.
Product Status: Discontinued; actively supported.
