Stanford SR550 and SR552 Input Voltage Preamplifier

The SR550 FET Input and SR552 BJT Input Voltage Preamplifiers are designed to work with any Stanford lock-in amplifier, providing gain where it is needed most - right at the experiment. These preamplifiers minimise noise and pick up in the connecting lines and can reduce measurement time in noise-limited experiments. The SR552 differs from the SR550 in its bipolar front-end design. The SR552 has a lower input noise and a correspondingly lower input impedance than the SR550.

SR550

• 3.6nV/ √Hz input noise
• FET intput, 100 MΩ input impedance
• Gain of 1, 2, 5 or 10
• Single-ended and differential inputs
• AC coupled input
• Powered by SRS lock-in amplifiers
• High common mode rejection

SR552

• 1.4 nV/ √Hz input noise
• BJT input, 100kΩ input impendance
• Gain of 10, 20, 50 or 100
• Single-ended and differential inputs
• AC coupled input
• Powered by SRS lock-in amplifiers

When used with the SR510 or SR530, the preamplifier gain is automatically set by the lock-in. When used with the SR850, SR810 or SR830, the gain is always set to 100. Power and control signals are brought from the lock-in by a 9-pin cable (included). The SR552 may also be operated independently by applying appropriate power supply voltages (±20VDC, +5VDC).