Verified calculation capability

MOSFET conduction loss Calculation Capability

Compute MOSFET conduction loss from I, Rds(on), current_basis (dc / on-interval RMS / full-cycle MOSFET RMS), and optional Rds(Tj) via linear α or datasheet ratio. · Electrical · Mosfet

Capability ID electrical.mosfet.conduction_loss · version 1.2.2

Open calculator REST API MCP Evidence Evidence JSON CVP Manifest Review policy

Model

On-interval RMS

On-interval RMS: P = I_on,rms² × Rds(on) × D
Full-cycle MOSFET RMS / DC: P = I_rms² × Rds(on)
Resistive drop at entered current: VDS estimate = I × Rds_Tj
Linear Rds(Tj): Rds(Tj) = Rds(Tref) × (1 + α × (Tj − Tref))
Datasheet ratio: Rds(Tj) = Rds(Tref) × rds_ratio

Inputs / Outputs

Canonical symbols for this capability. Agent schemas remain the contract.

Symbol	Quantity	Unit	Role
`I`	Current in amperes. Meaning depends on current_basis: DC amps, RMS during the MOSFET ON interval, or full-cycle MOSFET RMS.	—	input / output
`Rds`	On-resistance Rds(on) (Ω) at Tref (usually 25 °C). Use temperature_model to scale to Tj.	—	input / output
`D`	Duty cycle fraction in (0, 1]. Used only when current_basis=on_interval_rms. Ignored (warning DUTY_NOT_APPLICABLE) for dc and full_cycle_rms. Default 1.	—	input / output
`current_basis`	How I is defined. Required. dc: continuous current, P=I²·Rds_Tj, D=1. on_interval_rms: I is RMS while the FET is on, P=I²·Rds_Tj·D. full_cycle_rms: I is MOSFET RMS over the switching period, P=I²·Rds_Tj (do not multiply by D). The engine will not infer a waveform factor.	—	input / output
`temperature_model`	Rds(Tj) correction. none (default): use Rds as entered. linear: Rds_Tj=Rds·(1+α·(Tj−Tref)). ratio: Rds_Tj=Rds·rds_ratio. Omitting temperature_model infers ratio if rds_ratio is set (ratio wins even when Tj_C or alpha_per_C is also present), else linear if Tj_C or alpha_per_C is set, else none.	—	input / output
`Tj`	Junction temperature (°C). Required for temperature_model=linear.	°C	input / output
`Tref`	Rds reference temperature (°C). Default 25.	°C	input / output
`alpha_per`	Linear temperature coefficient (1/°C). Default 0.006 when linear and omitted — a Si MOSFET planning default, not a datasheet value.	°C	input / output
`rds_ratio`	Normalized Rds(Tj)/Rds(Tref) from the datasheet curve. Required for temperature_model=ratio.	—	input / output
`P`	Conduction loss at Rds_Tj (W). P=I²·Rds_Tj·D when current_basis=on_interval_rms; P=I²·Rds_Tj otherwise.	W	output
`V_drop`	Resistive voltage drop at the entered current using Rds_Tj: I·Rds_Tj (V).	—	output
`Rds_Tj`	Rds used in P_W (Ω). Equals Rds when temperature_model=none.	—	output
`P_W_ref`	Conduction loss at entered Rds / Tref (W). Present when a temperature model is applied.	—	output
`V_drop_ref`	I·Rds at Tref (V). Present when a temperature model is applied.	—	output

Assumptions / Validity

Declared scope for this capability. Do not use it outside this domain.

Assumptions

Constant Rds during on-time at the applied Rds_Tj.
current_basis is the contract for what I means; the engine will not guess a waveform factor.
No switching, Coss, or gate-drive loss.
Rds(Tj) is first-order linear or a datasheet ratio — not a physics compact model.
Default α = 0.006 /°C is a Si MOSFET planning default, not manufacturer validated.

Example

One numerical check. The calculator page holds worked steps and FAQ.

current_basis=dc, I=10, Rds=0.05, rds_ratio=1.44 → P_W=7.2, Rds_Tj=0.072, P_W_ref=5

Open this example in the calculator

Trust

CVP VERIFIED · CVP protocol 1.0.0-proposed · Engineering assurance. Computational verification is defined by CVP. Supplemental domain review (internal) and named expert review are defined by the Review policy and do not by themselves determine CVP conformance.

CVP: CVP VERIFIED · CVP protocol 1.0.0-proposed · Engineering assurance· View Manifest · CVP overview · Specification
Assurance: Engineering
Declared partition coverage: PASS · 4/4 declared partitions (dc, on_interval_rms, full_cycle_rms, invalid-domain)
Calculation version: 1.2.2
Verification: 32/32 calculation tests · 7/7 legacy golden · 13/13 legacy boundary · 8/8 legacy property
Production surface contract: 12/12
Versions: Calculation 1.2.2 · CVP protocol 1.0.0-proposed
CVP identity: 8/8 property · digest 77fa2f728b57
Reference: O1 model · O2 expected_values · O2 numerical_behavior
Interfaces: PASS · UI (SSR) / REST / MCP
ui-ssr is query-result HTML, not a live browser session.
CVP suite: 3/3 golden · 13/13 CVP boundary · 13/13 invalid · 8/8 property · 2/2 cross-interface · 12/12 CVP contract
Supplemental domain review: Internal · Pass · electrical-engineer · CalculatorX electrical review (EE-001) · 2026-08-14
Named expert review: Not performed
Version lock: Supported (409 VERSION_MISMATCH)
Artifact consistency: Build verified · 1.2.2 (workspace artifacts agree)
Review-policy tier: Internally reviewed — catalog token internally_reviewed; supplemental; not CVP status

This calculator CURRENT · Public schema 1.2.2 matches · Semantic contract ✓ · Production attested · Public/cache ✓ · Origin ✓

Call this capability

Human page, REST, and MCP share the same engine and calculation_version. Build verified hashes workspace artifacts only. After deploy, attest:production GETs canonical URLs twice — the public/cached view an Agent actually hits, and origin — including every /capabilities/{id} HTML page. Public Capability HTML version must match catalog before production attestation passes. Live Trust rows above fetch /.well-known/calculatorx-production-attestation.json and the output schema const. Build hashes: release integrity. That proves currently published page / engine / schema / evidence / MCP agree — not that a historical version is independently immutable. Reference Calculation Standard — Production surface contract 12/12.

Tool id: mosfet-conduction-loss
Engine: mosfet-conduction-loss
REST: POST /api/v1/calc/mosfet-conduction-loss
MCP: execute_calculation with capability_id: "electrical.mosfet.conduction_loss"
Agent input schema: Canonical (MCP / Agent)
Output schema: JSON Schema (latest)
Versioned input schema: Immutable pin (1.2.2)
Versioned output schema: Immutable pin (1.2.2)

Operations

Declared calculation modes for this capability.

dc
on_interval_rms
full_cycle_rms

References

Human-readable sources plus CVP reference evidence classes.

Sources

IEC 60747-8 — Semiconductor devices — Discrete devices — Part 8: Field-effect transistors — Drain-source on-state resistance RDS(on)
Infineon — OptiMOS device selection for synchronous rectification — Conduction losses P_cond = I_RMS² × RDS(on)
Texas Instruments SSZTB57 — How to Minimize MOSFET Conduction Loss in Battery-Powered Applications — P_cond = I_RMS² × RDS(on)
Erickson & Maksimović — Fundamentals of Power Electronics — Conduction loss in semiconductor switches
NIST Guide to the SI (SP 811) — SI units for current, resistance, and power

Reference evidence classes: O1 model · O2 expected_values · O2 numerical_behavior

Try with an agent

Inspect this capability via same-origin MCP, then call execute_calculation.

curl -sS -X POST 'https://www.calculatorx.com/mcp' \
  -H 'Content-Type: application/json' \
  -H 'MCP-Protocol-Version: 2026-07-28' \
  -H 'Mcp-Method: tools/call' \
  -H 'Mcp-Name: inspect_capability' \
  -d '{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"inspect_capability","arguments":{"capability_id":"electrical.mosfet.conduction_loss"}}}'

Inspect the trust tier and required assurance level before execution. Pin calculation_version (1.2.2) when reproducibility matters. Full protocol notes: MCP docs.