SR556 – Current preamplifier


  • Current preamplifier


SR556 – Current preamplifier


The SR556 is a low-noise, high-bandwidth, fixed-gain current (trans-impedance) amplifier designed to work with SRS lockin amplifiers. Current amplifiers provide gain close to the experimental detector, allowing the user to minimize input cable length and its corresponding input capacitance. The SR556 minimizes noise and pickup before they permanently degrade the signal-to-noise ratio, reducing measurement time in noise-limited experiments.


• 1 V/nA fixed gain
• 5 fA/√Hz input noise
• Bias voltage input
• Powered by SRS lock-in amplifiers


Technical Specifications

Gain: 109V/A
Bandwidth: 3 kHz (-3 dB)
Input noise (typ.): 5 fA/?Hz at 1 kHz
Current input
Impedance: 50 ?
Bias current: <3 pA
DC bias input
Range: ?5 VDC
Settling time: <250 ms
Impedance: 1 M?
Gain accuracy: 1 %
Gain stability: ?50 ppm/?C
Output: 20 Vpp max. balanced differential
10 mA max., 50 ?
Power: Supplied by SR510, SR530, SR810, SR830 or SR850 or SR124 via connector cable
Dimensions: 3.0″” ? 1.3″” ? 5.1″” (WHD)
Weight: 10 oz.
Warranty: One year parts and labor on defects in materials and workmanship