Keithley 502A

The Keithley 502A is a precision analog milliohmmeter engineered for accurate low-resistance measurements across laboratory and field environments. It delivers reliable readings without zero drift or thermal EMF errors, utilizing 13 overlapping ranges with linear scale indication for direct resistance value display. The instrument achieves 10 µΩ sensitivity and ±3% accuracy (±5% on the 1 mΩ range), making it well-suited for resistivity and contact resistance characterization.

## Technical Specifications

• **Resistance Ranges:** 13 overlapping ranges
• **Sensitivity:** 10 µΩ
• **Accuracy:** ±3% of full scale (±5% on 1 mΩ range)
• **Test Current:** 10 mA (1 mΩ to 10 mΩ range); down to 600 µA (1 kΩ range)
• **Power Dissipation:** <2 mW
• **Voltage Across Sample:** 360 hours
• **Design:** Analog

## Key Features

• Zero drift immunity and thermal EMF rejection
• Linear scale across multiple overlapping ranges for unambiguous reading
• Low test voltage and current to minimize sample heating and potential damage
• Extended battery life supporting continuous field deployment

## Typical Applications

• Contact and bond resistance measurement
• Resistivity characterization
• Low-resistance verification in electrical assemblies

## Compatibility & Integration

The 502A operates with battery types RM 401R, RM 42R, 412, and 413. Analog design allows direct integration into manual measurement workflows without external interfaces.