Fluke 1900A Multi-Counter

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

• 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.