CALCULATORS / WIRES, CABLES AND HARNESSES

Connector contact voltage drop and heating calculator

Constant contact resistance dissipation and voltage loss.

wires-contact-loss.napkin / editable

SCENARIO COMPARISON

Compare the numbers.

This source describes an analytical model. Its quantities and checks are the view.

Scenario	dropV	lossW
	0.1	0.5
	0.08	0.32

All calculated quantities are listed with the inputs. Switch to Source to inspect the equations.

SCENARIOS / CALCULATED VALUESSAME SOURCE

Change an input to see the consequences.

contact loss budget0.50 W✓ passes

BASELINE INPUTS

current5 Aresistance0.01 ohmcontacts2

CALCULATED

drop0.1 V

loss0.5 W

Edits change the baseline source.

THE SOURCE

Edits below update the same model.

# Connector contact voltage drop and heating
# Scope: Constant contact resistance dissipation and voltage loss.
# Status: illustrative worked example; engineering review pending.
# Inputs are example values. Checks are editable example requirements, not standards.

current = 5 A
resistance = 0.01 ohm
contacts = 2

drop := current*resistance*contacts [V]
loss := current^2*resistance*contacts [W]

check contact loss budget: loss <= 1 W

scenario alternative: current = 4 A

Calculated from your source · not saved

Baseline · Baseline

contact loss budget0.50 W ✓ passes

alternative · alternative

contact loss budget0.32 W ✓ passes

Illustrative first-order example. Checks are editable requirements, not design standards. The broader topic may require additional equations, data, and validation.

Formula and units

This example uses the following equations. Input names and units match the editable source above.

drop: drop = current*resistance*contacts [V]
loss: loss = current^2*resistance*contacts [W]

Original worked example

These are the baseline values in the downloadable source. Edits above let you test your own values.

Given

current: 5 A
resistance: 0.01 ohm
contacts: 2

Calculated

drop: 0.1 V
loss: 0.5 W

Assumptions and limits

Constant contact resistance dissipation and voltage loss.

The requirement checks use the limits written in this example. Passing a check does not establish that the model covers every load, material behavior, or operating condition in a real design.

Download this .napkin example ↓

Take it further with your agent

Napkin keeps the inputs, equations, checks and assumptions together in one study. Your agent sets it up; you change the numbers.

Try with Claude ↗

codex 'Use Napkin (https://napkin.engineering/mcp, or the local Napkin plugin) to build a study: Connector contact voltage drop and heating. Inputs: contact resistance; current sharing; duty; thermal model. Outputs: voltage drop; loss; conditional temperature estimate. Model scope: Conductor geometry and sourced installation/component limits. Read napkin_capabilities and the current snapshot. Ask me for the values that matter, label assumptions with units, author .napkin source, validate it and apply it with napkin_source using the current revision, then open the study. Add checks for the limits I supply. Keep unsupported analyses explicit.'

Claude needs the Napkin connector; Codex needs the Napkin plugin. Set up your agent ↗

The broader study

The topic brief below describes the broader scope. The worked example above states the particular calculation it implements.

Inputs: contact resistance, current sharing, duty, thermal model
Outputs: voltage drop, loss, conditional temperature estimate
Modes: calculate, compare, sweep
Drawing: Harness and voltage-drop diagram

EXECUTABLE WORKED EXAMPLE · FIRST-ORDER MODEL · CHECK THE SCOPE & ASSUMPTIONS