Product Description
Keithley 179 TRMS Digital Multimeter – 4.5 Digit Benchtop DMM
This used Keithley 179 is a precision 4.5-digit TRMS (True Root Mean Square) digital multimeter designed for accurate measurement of AC and DC voltage, AC and DC current, and resistance . It is a classic benchtop instrument from Keithley, a manufacturer renowned for high-quality measurement equipment.
About the Keithley 179 Series
The Keithley 179 and 179A were introduced in the late 1970s and early 1980s as versatile bench multimeters for laboratory and industrial use . They are known for their TRMS AC measurement capability, which provides waveform-insensitive accuracy for applications such as power supply design and testing .
Key Features & Specifications
| Specification | Details |
|---|---|
| Display | 4.5 digits |
| Sensitivity | 10µV AC and DC |
| DC Voltage Ranges | 200mV to 1200V in 5 ranges |
| DC Voltage Accuracy | ±(0.04% of reading) |
| DC Current Ranges | 200µA to 20A in 6 ranges |
| DC Current Accuracy | ±(0.02% of reading) (up to 2A); ±(0.5% of reading) (20A range) |
| AC Voltage Ranges | 200mV to 1000V in 5 ranges |
| AC Voltage Accuracy | ±(0.5% – 0.7% of reading) depending on range |
| AC Current Ranges | 200µA to 20A in 6 ranges |
| Resistance Ranges | 20kΩ to 20MΩ in 5 ranges |
| Resistance Accuracy (HI) | ±(0.04% of reading) (most ranges); ±(0.1%) (20MΩ range) |
| Resistance Accuracy (LO) | ±(0.15%) |
| Input Impedance (DC Volts) | 10MΩ |
| AC Frequency Range | 45Hz – 10kHz (current); 100Hz – 10kHz (voltage) |
| Crest Factor | 3 |
| Continuous Current | 15A continuous, 20A with 50% duty cycle |
| Special Features | HI/LO Ohms mode for semiconductor testing, 1kV protection on ohms, optional BCD/IEEE-488 output |
Special Features Explained
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TRMS AC Measurement: Provides accurate readings even for non-sinusoidal waveforms, essential for modern electronic testing .
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HI/LO Ohms: In HI mode, the meter applies enough voltage (2V) to turn on semiconductor junctions for testing. In LO mode (200mV), it allows in-circuit measurements without turning on junctions .
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Current Measurement: Can measure up to 20A (with duty cycle limitations) .
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Optional Interfaces: BCD (Model 1792) and IEEE-488 (Model 1793) outputs were available for automated test systems .
Accessories (Original, Not Included)
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Model 1691: General Purpose Test Lead Set (originally shipped with unit)
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Model 1788: Battery Pack for portable operation
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Model 1010/1017: Single/Dual Rack Mount Kits
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Model 1301: Temperature Probe
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Model 1600: High Voltage Probe
Condition
SOLD AS IS
USED – SHOWS NORMAL LAB WEAR (scuffs, rack marks, cosmetic wear)
UNTESTED – ACCURACY/FUNCTION NOT VERIFIED
NO TEST LEADS OR ACCESSORIES INCLUDED
FUSE CONDITION UNKNOWN
PICTURE MAY NOT MATCH PRODUCT
Potential Applications
-
General purpose bench testing
-
Educational laboratories
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Electronics repair and troubleshooting
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Quality control inspection
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Hobbyist and maker workshops
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Vintage equipment restoration
| Weight | 6.3 lbs |
|---|---|
| Dimensions | 18 × 12 × 6 in |
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