Abstract
We present a sensitive voltage amplifier suited for measurements of source impedances in the k $$\Omega$$ range at dilution refrigerator temperatures. The circuit is based on a commercial dc SQUID, an impedance matching transformer, and it works on the principle of negative feedback. At 10 mK, the amplifier contribution to the noise is only 17 $$\text{pV/}\sqrt{\text{ Hz }}$$ , which is negligible in comparison with the fluctuations of the thermal voltage of a 3.25 k $$\Omega$$ metallic source resistor. Various circuit parameters of the amplifier are discussed.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
