SIM is an acronym for Small Instrumentation Module, for devices in a family of electronic plug-in modules pioneered by Stanford Research Systems (SRS). These instruments provide a variety of analog-electronic functions to laboratory users. Though SRS offers a large line of such modules, TeachSpin has developed further modules to meet special electronic needs arising in the use of its Condensed-Matter Physics laboratory apparatus.

SRS makes a wide range of SIMs, and they can be seen in the SRS catalog – on the SRS Products page, look for ‘SIM Modules’. TeachSpin adopted the SIM technology for some of the electronic support in its CMP = Condensed-Matter Physics program. And the architecture is ‘open’; SRS will sell you an empty case of a SIM for you to populate with any electronic content you wish. SIMs from SRS have cases of live-grey color; SIMs from TeachSpin have bright-red cases.

SIMs come in ‘single-width’ and ‘double width’ modules, and they are designed to slide into a mainframe or ‘SIM crate’ which automatically connects them to SIM-crate power supplies. The power connections are made via a DB-15 connector built into the lower rear panel of each SIM enclosure. In addition to power, the SRS SIM crate connects SRS SIMs to various digital interconnections. Digital functions are not used in the TeachSpin SIMs.

Sliding a single- or double-width SIM into an SRS crate connects it to a 70-W power supply built into the SIM crate. The SRS crate has room for 8 single-width SIMs, or a mix of single- and double-width devices. It is not necessary to fill the crate. Users who want to power just one or two SIMs can buy from TeachSpin a small auxiliary power supply, adequate for powering one or two single-width, or one single- and one double-width SIM. The SRS mainframe, and the TeachSpin surrogate power supply, make available stabilized supply voltages of ±5 V, ±15 V, and +24 V. Each SIM has a back panel, and the lower half of this back panel bears a DB-15 subminiature connector which mates with a power-supply connection at the back of each slot in a SIM crate.

Each SIM may have input or output connections, as well as hand-accessible controls and readouts, on its front panel. Each SIM has access to the power, and (in some cases) digital communications systems, of the crate via its lower back panel. Some SIMs also use the upper back panel for input or output connections; wiring to these back-panel connections is accessible through the back of the SIM crate.

TeachSpin started building SIMs to support the needs of its users of CMP or condensed-matter physics experiments. Typically, users of the TeachSpin variable-temperature cryostat will have a SIM crate from SRS, populated with some SRS and some TeachSpin SIMs. Individuals SIMs from TeachSpin were developed to match particular needs in individual CMP experiments. But there is no need to confine a TeachSpin SIM to the experiment which motivated its construction. Because the SIMs might be more generally applicable in meeting needs in laboratory electronics, we welcome the use of our SIMs in contexts other than CMP experiments. That’s also why we also developed our stand-alone, crate-freeing, auxiliary power supply for SIMs.

Here’s a list, as of late 2019, or the SIMs we make (and the experiments that motivated their design). • PI Temperature Controller (built to support the TeachSpin cryostat) • Current Source (built to support the Electrical Transport experiment) • Dual Current Source (for exciting two channels of cryostat temperature transducers) • High-Gain Utility Amplifier (built for the Specific Heat experiment) • Pulse Current (built to deliver heat pulses in the Specific Heat experiment) • Hartshorn Coil-Driver (built to support the Magnetic-Susceptibility experiment) • High Tc Superconductivity (built to support the Hall probe used in persistent-current experiments)

You can find a paragraph-length guide for each SIM here. (https://www.teachspin.com/sims-manuals)At the end of each SIM's short-form guide, there's also a link to that SIM's multi-page manual. We've elected not to print and ship these manuals with the SIM hardware, but you're free to print either the guide or the manual for your own use.