The Stanford Research Systems SR510 is a single-phase lock-in amplifier that detects and measures weak AC signals buried in significant noise through precision analog demodulation. Using a sine-wave multiplier, the instrument translates input signals down to DC, enabling subsequent filtering and amplification with exceptional sensitivity across a broad frequency range.
Technical Specifications
Signal Channel
• Voltage input impedance: 100 MΩ + 25 pF (AC coupled)
• Current input impedance: 1 kΩ to virtual ground
• Current input gain: 10⁶ V/A
• Full-scale sensitivity (voltage): 100 nV to 500 mV
• Full-scale sensitivity (current): 100 fA to 0.5 µA
• Input noise (voltage): 7 nV/√Hz at 1 kHz
• Input noise (current): 0.13 pA/√Hz at 1 kHz
• Maximum input: 100 VDC, 10 VAC
• 60 Hz notch filter: 50 dB rejection, Q=10 (45–65 Hz adjustable)
• 120 Hz notch filter: 50 dB rejection, Q=10 (100–130 Hz adjustable)
• Tracking band-pass filter: Q=5, +20 dB dynamic reserve
Reference Channel
• Frequency range: 0.5 Hz to 100 kHz
• Input impedance: 1 MΩ (AC coupled)
• Sine trigger: 100 mV minimum, 1 Vrms nominal
• Pulse trigger: ±1 V, 1 µs minimum width
• Detection modes: Fundamental (f) and 2nd harmonic (2f)
• Internal oscillator output: 0.01, 0.1, or 1 Vrms, up to 20 mA drive
Demodulator & Output
• Pre-filter time constants: 1 ms to 100 s (6 dB/octave)
• Dynamic reserve: Up to 80 dB (with tracking band-pass filter)
• Frequency-voltage controlled oscillator: 1 Hz to 100 kHz
• Quadrant outputs: 0°, 90°, 180°, 270° phase shifts (1 Vrms sinewaves)
• Output meter: 2% precision analog, plus 4-digit LCD display
• Output BNC: ±10 V at full-scale input (<1 Ω impedance)
• Ratio output for servo applications
– Key Features
Precision analog sine-wave multipliers eliminate spurious harmonic responses. Dual notch filters suppress 60 Hz and 120 Hz interference. Selectable stability modes (5 ppm/°C to 500 ppm/°C) accommodate different operating conditions. Single-ended or differential voltage inputs with picoampere-level current sensitivity. Phase-locked detection at fundamental or second harmonic enables flexible measurement configurations.
– Typical Applications
Phase-sensitive detection of modulated signals. Characterization of low-impedance or high-impedance samples. Noise reduction in spectroscopy and materials analysis. Lock-in measurement of AC parameters in semiconductor and condensed-matter research.
