Model 372 AC Resistance Bridge and Temperature Controller

Latest-generation design for ultra-low temperature applications Lake Shore Model 372 AC Resistance Bridge & Temperature Controller Input Setup Curve Entry Remote/Local Exit Menu Output Setup Zone Settings Interface ^^^^^ Still Output Relay/Alarms _ Display Setup Still Output Relay/Alarms Instrument Setup Max/Min Reset ■ Patented noise rejection technology ■ Highly versatile and reliable measurement input ■ Ability to increase the number of measurement channels to a maximum of 16 with optional 3726 scanner ■ Dedicated input for ultra-low temperature control ■ Powerful impedance measurement capabilities...

Noise rejection Externally generated electronic noise can be a major cause of self-heating if it is allowed to couple into the device under test. Thankfully, multiple noise-rejection strategies have been implemented to reduce this effect substantially: By using alternating current (AC) measurement in tandem with a specially designed internal lock-in amplifier, the Model 372 is able to extract very small measurement signals from background noise. This allows for much lower excitation levels to be used when compared to traditional direct current (DC) systems, minimizing the amount of energy that...

Temperature measurement Measure a wide range of resistive devices Extremely accurate and reliable ultralow temperature measurements can be achieved by combining the Model 372 with a negative temperature coefficient (NTC) resistive temperature device (RTD), such as the Lake Shore Cernox™, Rox™ or germanium temperature sensors. Multiple calibration curves can easily be uploaded to the Model 372, allowing highly accurate conversion of sensor resistance to equivalent temperature using cubic spline interpolation (an improved interpolation technique compared to older instruments). With up to 22 different...

Dilution Refrigerator Temperature Control A Model 372 and 3726 used to control a dilution refrigerator Scanned temperature channels Making accurate measurements at ultra-low temperatures is no easy feat, especially when working in the ranges seen by modern dilution refrigerators. The Model 372 has many features specifically developed for dilution refrigerator applications. Dedicated temperature control input Taking measurements at ultra-low temperatures deserves uninterrupted attention from measurement devices. The Model 372 uses a dedicated temperature control input that is designed specifically...

Low-Power Impedance Characterization— the 3708 Scanner Many material characterization experiments require measurements to be performed at cryogenic temperatures. This can be because the material behavior changes in interesting ways at these temperatures, or because background thermal noise must be minimized for useful measurement data to be extracted. The standard inputs of the Model 372 accurately measure higher-impedance devices such as temperature sensors, but begin to lose resolution and accuracy when extremely low impedances are encountered such as in Hall effect or superconducting material...

Multiple simultaneous connections Available functions The 3708 scanner and preamp allows up to eight simultaneous connections to be made, with the scanner feature enabling measurement to be switched between those connections. Unlike the 3726 scanner, all connections that are not actively being measured are left open, allowing the 3708 to be connected to Hall bar devices. Multiple actions can be performed when connected to the Model 372 through one of its various remote access options: Overcoming cable length DD Live graphical viewing of data using the Lake Shore Cryotronics Chart Recorder software...

Sensor performance Excitation ranges in sensor tables were selected to minimize sensor self-heating. Excitation power = actual current2 × example resistance Measurement resolution comes from electronic instrumentation and sensor thermal noises. Measurement resolution is given by: Resolution (Ω) = ((instrument noise at RT)2+(thermal noise of sensor at given temperature)2)0.5 or Resolution(Ω) Resolution (Ω) = (Ni2+Ns2)0.5 Resolution (K) = (dR/dT) Where: Ni = instrument noise at room temperature Ns = thermal noise of resistive sensor at given temperature Electronic accuracy is influenced by the...

Lake Shore GR-50-AA with 0.05 to 6 K calibration Values given are for measurement input. If the value is different for the control input, it is shown in blue. Sensor properties Temperature Nominal resistance Typical sensor sensitivity Excitation and instrumentation Thermal Resistance Excitation Excitation Power resistance range voltage current limit Instrument performance Measurement resolution Electronic accuracy Overall performance Calibration Self-heating Interpolation Overall accuracy accuracy errors error Lake Shore CX-1010-SD with 0.1 to 325 K calibration Values given are for measurement...

372/3726 performance specification table The values below apply to the measurement input. The control input operates over a reduced range indicated by the black-bordered cells. These cells contain bracketed numbers to indicate the resolution that applies to the control input. Voltage range Current excitation 632 mV 200 mV 63.2 mV 20 Ω 6.32 Ω 2Ω 20 µΩ 6.3 µΩ 2 µΩ 10 mW 3.2 mW 1 mW 63.2 Ω 20 Ω 6.32 Ω 63 µΩ 20 µΩ 6.3 µΩ 3.2 mW 1 mW 320 µW 200 Ω 63.2 Ω 20 Ω 200 µΩ 63 µΩ 20 µΩ 1 mW 320 µW 100 µW 632 Ω 200 Ω 63.2 Ω 630 µΩ 200 µΩ 63 µΩ 3.2E-04 100 µW 32 µW 2 kΩ 632 Ω 200 Ω 2 mΩ 630 µΩ 200 µΩ 100 µW...

372/3708 performance specification table Current excitation resistance range resolution power Resistance range: Full scale resistance range, nominal 20% over range. Resolution: RMS noise with 18 s filter settling time (approximates 3 s analog time constant). Noise specified at ½ full scale resistance at room temperature. Power: Excitation power at one-half full s