The Fluke 1900A Multi-Counter is a precision instrument for frequency and period measurements across laboratory and field environments. It delivers accurate counting and signal analysis from 5 Hz to 80 MHz, with selectable resolution, period averaging, and totalize functions. The instrument features high input impedance, a six-digit LED display with automatic decimal positioning, and signal conditioning for challenging electrical environments. A discontinued model, it remains supported through third-party suppliers and integrates with optional data output systems for automated test workflows.
Technical Specifications
Measurement Functions
• Frequency: 5 Hz to 80 MHz
• Period: 5 Hz to 1 MHz
• Totalize: 1 to 999,999 counts
• Frequency resolution: 0.1 Hz, 1.0 Hz, 10 Hz, or 100 Hz (manually selectable)
• Period averaging: 10¹, 10², 10³, or 100 periods (manually selectable)
Sensitivity
• Frequency and totalize (sine wave): 15 mV rms, 5 Hz to 80 MHz
• Frequency and totalize (pulse): 200 mV P-P minimum, 20 nsec pulse width minimum, >10% duty cycle
• Period (pulse): 200 mV P-P minimum, 200 nsec pulse width minimum, >10% duty cycle
Input & Signal Conditioning
• High input impedance to minimize circuit loading
• Selectable 1 MHz low-pass filter for noise-heavy environments
• Selectable 10:1 attenuator for high-level signal inputs
Display & Output
• Six-digit LED display with leading-zero suppression
• Automatic decimal point positioning
• Unit annunciators (kHz, MHz, milliseconds, microseconds) and overflow indication
• Parallel BCD data output available via optional Data Output Unit (DOU)
• Self-check mode for performance verification
Power & Physical
• Line-powered: 100, 115, or 230 V AC at 50–400 Hz; 6.5 W consumption
• Optional battery-powered version (Model 1900A-01) with rechargeable nickel-cadmium cells
• Dimensions: 6 × 19 × 25 cm
– Key Features
• Autoranging with manual override for resolution and period averaging
• Dual-mode sensitivity for sine wave and pulse signals
• Compact benchtop footprint with intuitive six-digit readout
• Multiple power options for stationary or portable deployment
– Typical Applications
Frequency verification in component testing, period measurement in timing analysis, signal counting in production environments, and diagnostic measurements in service facilities.
– Compatibility & Integration
Optional Data Output Unit enables parallel BCD format output at rear-panel connector for integration with automated measurement systems. Battery-powered variant (Model 1900A-01) provides flexibility for field applications while retaining full AC line operation capability.
