Keithley 179

The Models 179 and 179-20A are versatile digital multimeter useful for measurement of ac and dc voltage, ac and dc current and resistance.

The Model 179-20A is identical to the Model 179, except for an added 20-ampere range. This extra range uses separate input terminals and allows continuous measurement of up to l5A ac/dc or intermittent duty measurements up to 20A ac/dc.

Information headed by Model 179 is common to both the model I79 and the model 179-20A. Ranges and functions are selected with front panel pushbuttons.

The decimal point is also positioned by the selected range pushbutton. Polarity of the measured signal is automatically displayed.

Most of the measurement capabilities are provided by the Keithley 179 multimeter with 4 1/2 digit readout.

Keithley 179 is basically a sensitive ammeter that can be configured to measure ac and dc voltage, ac and dc current, and resistance.

Be aware that in ac mode, the multimeter would give a null reading if connected to a dc signal, since there would be no time-varying component.

With the Keithley 179 multimeter, voltages in the 2 V range can be measured with a resolution of 100 microV and an accuracy given by the numerical weight of the least significant digit (for example, 0.1 mV for a displayed reading of 123.4 mV) plus 0.04% when properly calibrated, as stated in the instruction manual.

For example, a reading of 1.9837 V has a least significant digit of 0.0001 V (0.1 mV); 0.04% of the reading is 0.8 mV. The resulting uncertainty in the reading is actually about 1.0 mV and should be recorded as 1.984 +/- 0.001 V. Thus the 4 1/2 digit readout is really only good.