{ "openapi": "3.1.1", "info": { "title": "PCB Trace Estimator API", "version": "1.0.0", "summary": "Estimate trace width or current capacity", "description": "Every endpoint performs the same calculation as the human page and returns inputs, result, units, assumptions, sources, warnings and computedAt. MCP endpoint: /mcp." }, "servers": [ { "url": "https://ohmforgepcbtraceestimator.usefulweb.app" } ], "paths": { "/api/v1/calculate": { "post": { "operationId": "calculate", "summary": "Estimate trace width or current capacity", "description": "Estimate copper trace width or current, resistance, voltage drop, and power loss using the IPC-2221 equation.\n\nMethodology:\n- Uses the empirical IPC-2221 relation I = k × ΔT^0.44 × A^0.725, with copper cross-sectional area in square mils. The coefficient is 0.048 for external and 0.024 for internal layers.\n- Solves the equation for cross-sectional area and width, or solves for current at a given width. A nominal 1 oz/ft² copper weight is converted to 0.0348 mm.\n- Estimates resistance at 20 °C from copper resistivity 1.72 × 10⁻⁸ Ω·m and the specified length and area; voltage drop is I × R and power loss is I² × R.\n- Flags inputs outside the IPC-2221 chart range (up to 35 A, widths up to 400 mil, 10–100 °C rise, 0.5–3 oz/ft² copper), where the curve fit is an extrapolation.\n\nAn empirical estimate for an isolated rectangular trace, not a fabrication design-rule check or board-level thermal analysis. Resistance, voltage drop and loss use copper resistivity at 20 °C and do not include heating, plating, vias or adjacent copper. Input limits are numerical safeguards, not a validated operating range; verify the finished copper thickness and design with your fabricator.", "tags": [ "apps" ], "x-mcp-tool": "ohmforge_pcb_trace_estimator", "requestBody": { "required": true, "content": { "application/json": { "schema": { "$ref": "#/components/schemas/OhmforgePcbTraceEstimatorInput" }, "examples": { "example1": { "summary": "Width for 1 A on external 1 oz copper", "value": { "mode": "width", "layer": "external", "currentA": 1, "copper": 1, "copperUnit": "oz", "temperatureRiseC": 10, "length": 100, "lengthUnit": "mm" } }, "example2": { "summary": "Current for a 20 mil internal trace", "value": { "mode": "current", "layer": "internal", "width": 20, "widthUnit": "mil", "copper": 1, "copperUnit": "oz", "temperatureRiseC": 10, "length": 4, "lengthUnit": "in" } } } } } }, "responses": { "200": { "description": "Calculation result envelope.", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/OhmforgePcbTraceEstimatorResult" } } } }, "400": { "description": "Malformed JSON body.", "content": { "application/problem+json": { "schema": { "$ref": "#/components/schemas/Problem" } } } }, "422": { "description": "Invalid input (see errors[]).", "content": { "application/problem+json": { "schema": { "$ref": "#/components/schemas/Problem" } } } }, "429": { "description": "Rate limit exceeded (see Retry-After).", "content": { "application/problem+json": { "schema": { "$ref": "#/components/schemas/Problem" } } } } } } }, "/api/v1/tool": { "get": { "operationId": "getToolDefinition", "summary": "Inputs, output schema and examples for this tool", "responses": { "200": { "description": "Tool definition.", "content": { "application/json": { "schema": { "type": "object" } } } } } } } }, "components": { "schemas": { "Problem": { "type": "object", "description": "RFC 9457 problem details. 422 responses include per-field `errors`.", "required": [ "type", "title", "status", "detail" ], "properties": { "type": { "type": "string" }, "title": { "type": "string" }, "status": { "type": "integer" }, "detail": { "type": "string" }, "code": { "type": "string" }, "errors": { "type": "array", "items": { "type": "object", "required": [ "field", "message" ], "properties": { "field": { "type": "string" }, "message": { "type": "string" } } } } } }, "OhmforgePcbTraceEstimatorInput": { "type": "object", "additionalProperties": false, "properties": { "mode": { "title": "Calculate", "type": "string", "enum": [ "width", "current" ], "default": "width" }, "layer": { "title": "Copper layer", "type": "string", "enum": [ "external", "internal" ], "default": "external" }, "currentA": { "title": "Current (used when calculating width)", "type": "number", "minimum": 0.000001, "maximum": 10000, "default": 1, "x-unit": "A" }, "width": { "title": "Trace width (used when calculating current)", "type": "number", "minimum": 0.000001, "maximum": 100000, "default": 0.5 }, "widthUnit": { "title": "Width unit", "type": "string", "enum": [ "mm", "mil" ], "default": "mm" }, "copper": { "title": "Copper thickness", "type": "number", "minimum": 0.000001, "maximum": 10000, "default": 1 }, "copperUnit": { "title": "Copper thickness unit", "type": "string", "enum": [ "oz", "mm" ], "default": "oz" }, "temperatureRiseC": { "title": "Allowed temperature rise above ambient", "type": "number", "minimum": 0.01, "maximum": 1000, "default": 10, "x-unit": "°C" }, "length": { "title": "Trace length", "description": "Used for the resistance, voltage drop and power loss estimates.", "type": "number", "minimum": 0, "maximum": 1000000, "default": 100 }, "lengthUnit": { "title": "Length unit", "type": "string", "enum": [ "mm", "in" ], "default": "mm" } }, "required": [] }, "OhmforgePcbTraceEstimatorResult": { "type": "object", "additionalProperties": false, "required": [ "schemaVersion", "tool", "computedAt", "inputs", "summary", "result", "units", "assumptions", "sources", "warnings", "presentation", "links" ], "properties": { "schemaVersion": { "type": "string", "const": "1.0" }, "tool": { "type": "object", "additionalProperties": false, "required": [ "id", "name", "version" ], "properties": { "id": { "type": "string" }, "name": { "type": "string" }, "version": { "type": "string" } } }, "computedAt": { "type": "string", "format": "date-time" }, "inputs": { "type": "object", "description": "Normalised inputs actually used, including applied defaults." }, "summary": { "type": "string" }, "result": { "type": "object", "required": [ "mode", "layer", "currentA", "widthMm", "widthMil", "copperThicknessMm", "temperatureRiseC", "lengthMm", "areaMm2", "resistanceOhms", "voltageDropV", "powerLossW", "withinChartRange" ], "properties": { "mode": { "type": "string", "enum": [ "width", "current" ] }, "layer": { "type": "string", "enum": [ "external", "internal" ] }, "currentA": { "type": "number" }, "widthMm": { "type": "number" }, "widthMil": { "type": "number" }, "copperThicknessMm": { "type": "number" }, "temperatureRiseC": { "type": "number" }, "lengthMm": { "type": "number" }, "areaMm2": { "type": "number" }, "resistanceOhms": { "type": "number" }, "voltageDropV": { "type": "number" }, "powerLossW": { "type": "number" }, "withinChartRange": { "type": "boolean", "description": "False when current, width, temperature rise or copper weight lie outside the IPC-2221 chart range." } }, "additionalProperties": false }, "units": { "type": "object", "additionalProperties": { "type": "string" } }, "assumptions": { "type": "array", "items": { "type": "string" } }, "sources": { "type": "array", "items": { "type": "object", "additionalProperties": false, "required": [ "title" ], "properties": { "title": { "type": "string" }, "url": { "type": "string" }, "publisher": { "type": "string" }, "retrievedAt": { "type": "string" }, "note": { "type": "string" } } } }, "warnings": { "type": "array", "items": { "type": "string" } }, "presentation": { "type": "array", "items": { "type": "object" }, "description": "Display blocks used by the human page (same data)." }, "links": { "type": "object", "additionalProperties": false, "required": [ "human", "api", "openapi", "methodology" ], "properties": { "human": { "type": "string", "format": "uri" }, "api": { "type": "string", "format": "uri" }, "openapi": { "type": "string", "format": "uri" }, "methodology": { "type": "string", "format": "uri" } } } } } } } }