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Regulator Dissipation

A linear regulator throws away the voltage difference as heat: P = (V_in − V_out) × I. Efficiency is just V_out/V_in, so dropping 12 V to 3.3 V wastes about 70% of the energy.

Input voltage (V)

Output voltage (V)

Output current (A)

Dissipation

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Efficiency

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Rise at 50 °C/W

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The rise figure assumes a bare package at 50 °C/W. Above ~1 W you almost always need a heat sink — size it with the heat-sink tool.

A helper, not a substitute for engineering judgment. Verify against the governing standard.