Lake Shore 120CS

The Lake Shore 120CS is a precision DC current source engineered for stable, accurate current outputs in sensor excitation and measurement applications. It delivers switch-selectable output current from 1 µA to 100 mA with an 11 V compliance voltage, ensuring constant current across varying load conditions. Front-panel polarity reversal and rear-panel external programming via resistor network enable flexible current configuration. The unit is manufactured in the USA. Note: The Model 120CS has been discontinued; Lake Shore recommends the Model 121 DC current source as a replacement.

## Technical Specifications

• Output Current: 1 µA to 100 mA (switch-selectable)
• Compliance Voltage: 11 V (up to 50 mA); 10 V (above 50 mA)
• Current Accuracy: 0.05% of output at 10 µA
• Temperature Coefficient: <0.01% of output per °C
• Line Regulation: <0.01% change
• Load Regulation: <0.01% change
• AC Current Ripple: <0.01% of scale
• Operating Temperature: 15 °C to 35 °C
• Power Supply: External AC wall-mount (120 VAC or 210–250 VAC selectable); jumper-configurable
• Physical: 106 mm W × 41 mm H × 158 mm D; 0.5 kg

## Key Features

• Switch-selectable current range simplifies bench operation
• Front-panel OUTPUT switch enables rapid polarity reversal
• External programming input via rear-panel terminal block allows custom current levels from 1 µA to 100 mA
• Compliance indicator (CMPL) alerts when voltage limit is reached
• Compact benchtop form factor with minimal footprint

## Typical Applications

• Sensor excitation for resistance temperature detectors and diode sensors
• Precision current biasing in cryogenic measurement systems
• Stable DC current sourcing across variable impedance loads

## Compatibility & Integration

The 120CS excites Lake Shore 400-Series, 500-Series, and TG-120 Diode Sensors. It operates reliably in liquid helium (LHe) and liquid nitrogen (LN2) environments, supporting low-temperature measurement workflows.