Product Overview

The Fluke 773​ is the flagship of Fluke’s milliamp process clamp meter family, a handheld, battery-powered instrument built specifically for technicians and instrumentation engineers who work on 4-20 mA process control loops. Unlike a conventional multimeter, which forces you to open the circuit and insert the meter in series, the Fluke 773​ measures loop current non-invasively: you simply clamp the jaw around a single signal wire and read the current, so the process keeps running and the controller never loses its input. This single capability is why the Fluke 773​ has become the default troubleshooting tool in process plants, water and wastewater facilities, HVAC and building automation systems, and anywhere analog instrumentation is dense.What elevates the Fluke 773​ above the 771 and 772 in the same family is its full signal-chain capability. In addition to clamp-based and in-circuit mA measurement, it sources 4-20 mA for driving control system inputs, I/P converters and valve positioners; it simulates 4-20 mA while accepting an external loop supply of up to 50 V DC; it provides 24 V loop power so a transmitter can be energized and tested on the bench; and it both measures and sources DC voltage, verifying 24 V supplies and testing 1-5 V or 0-10 V input devices. Accuracy is best-in-class at 0.2% with 0.01 mA resolution and sensitivity, and the dual backlit display shows both the absolute mA value and the percentage of 4-20 mA span simultaneously.Designed for real panel work, the Fluke 773​ features a detachable clamp on an extension cable that reaches wires buried in crowded terminal cabinets, a measurement spotlight that illuminates dark enclosures, a Hold function for capturing drifting readings, and automatic 25% step or linear ramp output for remote testing and stroke checks. Powered by four AA batteries and rated IP40, it is a genuinely portable one-tool replacement for a loop calibrator, a DMM and a current source on routine service calls.

Technical Specifications

Main Features and Advantages

Non-invasive loop measurement: The defining advantage of the Fluke 773​ is that it reads 4-20 mA signals without breaking the loop, which Fluke rates as roughly five times faster than the traditional DMM method of opening the circuit and inserting test leads. Because the process never stops, intermittent faults that only appear under live conditions stay visible, and there is no risk of leaving a loop open after the test. The Fluke 773​ resolves down to 0.01 mA with 0.2% accuracy, sensitive enough to detect the small drift that indicates a failing transmitter or a wetted terminal.Measure, source, simulate and power in one tool: Where a basic clamp meter only reads, the Fluke 773​ closes the whole diagnostic circle. It sources 0-24 mA into loads up to 1,000 Ω to drive and stroke a valve or test a PLC analog input. In simulate mode it behaves as a two-wire transmitter, sinking current from an external supply of up to 50 V DC so a control card can be verified without a real field device. The 24 V loop power supply lets you energize a transmitter on the bench and simultaneously read its output in-circuit, which turns a two-person, two-instrument job into a one-person task.Voltage capability for mixed-signal panels: The Fluke 773​ also measures 0-30 V DC and sources 0-10 V DC, so the same instrument checks 24 V power supplies and validates the 1-5 V and 0-10 V inputs still common in building automation, drives and older DCS cards. Automatic linear ramp and 25% step output make stroke testing and remote calibration straightforward, and the Hold button freezes a fluctuating reading so you can write it down.Built for the cabinet, not the bench: A detachable clamp jaw on an extension cable lets the Fluke 773​ reach a single wire in a dense terminal block, while the measurement spotlight lights up the wire you are trying to see. The dual backlit display, auto-off and backlight timeout extend practical battery life, and the scaled mA output mirrors the clamped signal so a logging DMM such as the Fluke 289 can record a loop trend for hours without interrupting it.