{"sections":[{"heading":"Identify the intended branch","paragraphs":["RN is the normal resistance; R0 is the subgap resistance. RTYPE selects the subgap treatment. The maintained reference documents RTYPE=0 with conductance 1/RN and RTYPE=1 with a subgap branch based on R0 under its stated gap conditions.","For a fitted constant-resistance RSJ-style model, check whether RTYPE=0 and the intended RN express the chosen approximation. This is a modelling choice, not a universal replacement for an RCSJ model."]},{"heading":"Check temperature and scaling","paragraphs":["Model T and TC enable temperature-dependent RCSJ behaviour. Instance area also changes scaled parameters. Check these settings when a nominal RN/R0 comparison seems inconsistent.","Use .TEMP and device noise attributes for the documented thermal-noise excitation. Do not assume a noise-temperature command and model-temperature parameters have identical effects."]},{"heading":"Limits of a fitted parameter","paragraphs":["A constant or bias-stepped resistance fit is not automatically a runtime current-dependent RN model. Re-evaluate the selected model against the intended physics rather than inferring an unsupported expression from a fitted sweep."]}],"canonical_url":"https://www.sun-magnetics.com/knowledge-base/josim-junction-resistance","url":"/knowledge-base/josim-junction-resistance","known_issues":[],"search_record":{"execution":false,"relatedProducts":[],"version_tags":["JoSIM-Pro 2.9 target"],"text":"RN, R0 and temperature give unexpected junction resistance Check the selected junction model and RTYPE. Noise temperature and temperature-dependent junction behaviour are separate settings. JoSIM-Pro 2.9.0 release target; review-build/source evidence Explanation Identify the intended branch RN is the normal resistance; R0 is the subgap resistance. RTYPE selects the subgap treatment. The maintained reference documents RTYPE=0 with conductance 1/RN and RTYPE=1 with a subgap branch based on R0 under its stated gap conditions. For a fitted constant-resistance RSJ-style model, check whether RTYPE=0 and the intended RN express the chosen approximation. This is a modelling choice, not a universal replacement for an RCSJ model.  Check temperature and scaling Model T and TC enable temperature-dependent RCSJ behaviour. Instance area also changes scaled parameters. Check these settings when a nominal RN/R0 comparison seems inconsistent. Use .TEMP and device noise attributes for the documented thermal-noise excitation. Do not assume a noise-temperature command and model-temperature parameters have identical effects.  Limits of a fitted parameter A constant or bias-stepped resistance fit is not automatically a runtime current-dependent RN model. Re-evaluate the selected model against the intended physics rather than inferring an unsupported expression from a fitted sweep. ","id":"josim-junction-resistance","keywords":"","kind":"Explanation","title":"RN, R0 and temperature give unexpected junction resistance","product":"JoSIM-Pro"},"version":"2.9.0 release target; review-build/source evidence","id":"josim-junction-resistance","related":["/knowledge-base/josim-iv-characterisation","/knowledge-base/josim-iv-result-checks","/knowledge-base/josim-model-syntax","/knowledge-base/josim-noise-settings"],"downloads":[],"publication_status":"published","numerical_output":null,"provenance":{"execution_checks":[],"figure_evidence":[],"review_notes":["The owner accepted the modelling explanation on 2 November 2026. Applicable release/platform and unrecorded walkthrough checks remain pending."],"scope":"Recorded inputs/builds only. Complete walkthrough and final-package acceptance remain separate.","verification_requirements":{"gui_method":"not-required-for-this-answer","status":"review-incomplete","illustrations":"not-required-for-this-answer","required":["technical-review","release-applicability"],"legacy_walkthrough_field":"pending retained; not evidence of a complete scenario"},"sources":[{"id":"support:SUP-015","section":"Generalised editorial finding; outcome qualification retained"},{"id":"josim-pro:docs/manual_source/sections/syntax.tex","section":"Josephson junction model parameters; small-signal quasiparticle branch"},{"id":"owner:technical-review-20261102","section":"JoSIM-Pro 2.9 chosen as the public starting path; release availability must be checked before publication"}]},"title":"RN, R0 and temperature give unexpected junction resistance","type":"Explanation","markdown_url":"/_functions/kbResource?path=markdown%2Fjosim-junction-resistance.md","summary":"Check the selected junction model and RTYPE. Noise temperature and temperature-dependent junction behaviour are separate settings.","product":"JoSIM-Pro"}