Stanford Research Systems SR510 Single Phase Lock-In Amplifier

The Stanford Research Systems SR510 is a single-phase lock-in amplifier designed to extract low-level AC signals from noisy environments using precision analog sine-wave demodulation. Unlike square-wave multiplier designs, the SR510 employs a precision analog sine-wave multiplier to eliminate spurious harmonic responses, delivering high sensitivity and exceptional stability across a broad range of measurement applications.

– Technical Specifications

Signal Channel
• Differential voltage and current inputs
• Voltage input impedance: 100 MΩ (AC coupled), ~25 pF
• Current input impedance: 1 kΩ to virtual ground
• Input noise voltage: 7 nV/√Hz at 1 kHz
• Input noise current: 0.13 pA/√Hz at 1 kHz
• Full-scale sensitivity: 100 nV to 500 mV (voltage); 100 fA to 0.5 µA (current)
• Current input gain: 10⁶ V/A
• Maximum input: 100 VDC, 10 VAC

Reference Channel
• Frequency range: 0.5 Hz to 100 kHz
• Input impedance: 1 MΩ (AC coupled)
• Trigger modes: Sine wave or pulsed edge detection
• Minimum sine-wave amplitude: 100 mVrms; nominal 1 Vrms

Demodulator and Filtering
• Precision analog sine-wave multiplier
• Dual time constants: 1 ms to 100 s (6 dB/octave slope)
• Dynamic reserve: 20–60 dB (80 dB with band-pass filter)
• Line notch filter: 50 dB rejection at 45–65 Hz
• Second harmonic filter: 50 dB rejection at 100–130 Hz
• Tracking band-pass filter: Q = 5, auto-tracks reference frequency

Internal Reference Oscillator (optional)
• Voltage-controlled frequency: 1 Hz to 100 kHz
• Output amplitudes: 0.01, 0.1, or 1 Vrms (adjustable)
• Drive capability: up to 20 mA

Outputs and Interfaces
• Analog outputs: X, X Offset, X Noise
• Four ADC inputs: ±10.24 VDC range, 2.5 mV resolution, 1 kHz digitization
• Two DAC outputs: ±10.24 VDC range, 2.5 mV resolution
• Analog meter: 2% precision
• 4-digit LCD display
• RS-232 (standard); GPIB (optional)

– Key Features

• Analog sine-wave demodulation eliminates harmonic distortion
• Ultra-low input noise enables femtoampere and nanovolt sensitivity
• Selectable dual time constants for flexible noise filtering
• High dynamic reserve with optional band-pass enhancement
• Multiple reference trigger options for diverse signal sources
• Integrated oscillator with voltage control and variable output levels

– Typical Applications

• Optical detection and photometry
• Sensor characterization and calibration
• Material property measurements
• Magnetic resonance and related studies
• Precision low-level AC signal recovery

– Compatibility & Integration

RS-232 interface enables direct computer control; optional GPIB support extends integration with legacy test systems. Both ADC and DAC provisions allow closed-loop measurement and feedback applications. Adjustable internal reference oscillator with voltage control supports frequency-sweep and modulation experiments.