The DL Instruments/Ithaco 1211 Current Preamplifier is a precision analog instrument for amplifying small AC currents in measurement and signal processing applications. It delivers exceptionally low noise and stable gain across nine current sensitivity decades, making it ideal for photodiode, current transducer, and electrochemical cell measurements. The front-panel adjustable rise time, calibrated current suppression, and selectable detector bias supply enable flexible configuration for diverse laboratory and bench environments.
## Technical Specifications
**Sensitivity and Gain**
• Current sensitivity ranges: 10⁻³ to 10⁻¹¹ A/V across nine decades
• Gain multiplier: ×0.1, ×1.0, ×10 for dynamic range optimization
• Gain accuracy: ±2% (10⁻³ to 10⁻⁹ A/V); ±3% (10⁻⁹ to 10⁻¹¹ A/V)
• DC open-loop gain: >250,000
**Stability and Noise**
• Output stability: <0.003% per °C or per day
• Gain stability: 0.05% per °C or per day
• Output voltage offset stability: <0.003% per °C
• Input noise: 1.5 × 10⁻¹⁵ A rms/√Hz
• Output noise: <40 nV/√Hz
• Dynamic range: 96 dB (×1 multiplier, minimum rise time, 100 pF input shunt)
**Frequency Response**
• Bandwidth: 100 kHz (standard); up to 400 kHz AC coupled
• Rise time: Adjustable 10 μs to 1 s (1-3-10 sequence); <5 μs minimum
• Rolloff: 12 dB/octave standard; 6 dB/octave via jumper
**Input Characteristics**
• Input leakage current: ±25 pA max @ 25°C
• Input offset current: <10 pA; 1 GΩ DC coupled (typically 5 GΩ); 100 MΩ AC coupled
• Input offset nulling: Adjustable to 0 V
**Current Suppression & Bias**
• Calibrated suppression: Eight ranges, 10⁻³ to 10⁻¹⁰ A
• Detector bias: 0–5 V, adjustable polarity; 100 ppm/°C stability
**Output Characteristics**
• Output impedance: 600 Ω (also 50 Ω and unity gain options)
• Output swing: ≥15 V p-p (5 V rms)
• Output polarity: Inverted
## Key Features
• Nine decade current sensitivity with ±2–3% accuracy
• Exceptionally low input noise and stable DC offset
• Front-panel rise time adjustment for measurement bandwidth control
• Built-in current suppression and selectable detector bias supply
• TTL-compatible gating for multiplexed operation
• Classic analog design free from microprocessor-related noise artifacts
## Typical Applications
• Photodiode transimpedance amplification
• Current transducer signal conditioning
• Electrochemical impedance and voltammetry measurements
• Low-level AC current detection in physics and materials research
## Compatibility & Integration
Dual BNC inputs support AC and DC coupled signal paths. Multiple output impedances (600 Ω, 50 Ω, unity gain) accommodate diverse downstream instrumentation. TTL logic gating enables integration into automated measurement systems.
