The 3478A provides a low cost, full function, reliable DMM for system measurements. Selectable 3 1/2 to 5 1/2 digit resolution and 5 autoranging functions offer flexibility in automated testing. The 3478A can measure DCV, true RMS ACV, 2- and 4-wire ohms, and dc and ac current. Simple, fast electronic calibration eliminates all adjustments to provide a lower cost of ownership. Selectable speed and resolution provide the right capability for your measurement. The 3478A can perform production tests or acquire experimental data at 90 readings/s with 3 1/2 digit resolution, or take 35 readings/s with 130 dB of noise rejection using 4 1/2 digits. The 5 1/2 digit mode offers 100 nVdc and 100 ?W resolution for precise measurements. True RMS with 300 kHz bandwidth and 4:1 crest factor provides reliable measurements of ac signals. Fast autoranging makes the first reading useful and accurate. Switchable front/rear inputs permit flexible system connections. The Voltmeter Complete output and External Trigger input allow synchronization of the 3478A with a scanner for fast multiplexed measurements without the delay of software commands. The test program can write prompt messages or results on the alphanumeric display. The operator can respond by pressing the 3478A's SRQ key to interrupt the controller and start the next test. Built-in self-test capability assures proper operation.