Transformers and Power Supplies
Linear Regulator Heat Calculator
Linear Regulator Heat helps you find regulator heat from voltage dropped and load current. The page keeps the arithmetic visible so you can check the result against the original measurements.
Set up the Linear Regulator Heat case
Use measurements from one operating condition.
Understanding the equation
Start with the equation Pheat = voltage drop × current. The participating entries are Voltage dropped and Load current.
The initial scenario returns 10.50 W. Re-enter field data before using the answer in a design or comparison.
Calculate regulator heat from voltage dropped and load current. For the companion battery heat calculation, open Battery Heat Generation Calculator.
Interpreting the answer
The calculated Regulator heat is meaningful only with its input conditions attached. Compare it with component ratings and isolation requirements.
A result without its source conditions is difficult to compare or audit. If you also need series resistance, continue with LED Resistor Calculator.
Input notes
Use voltage and current values from the same side of the transformer or converter. Do not combine a worst-case value with unrelated nominal data.
Check every prefix before entry; micro, milli, kilo, and mega are not interchangeable. Continue with Joule Heating Calculator to evaluate heat energy.
- Voltage dropped
- Default example: 7 V. Enter voltage dropped in V.
- Load current
- Default example: 1.5 A. Enter load current in A.
Practical limits
Thermal resistance determines junction temperature.
The surrounding system may introduce diode loss, ESR, regulation, ripple current, and thermal resistance. Document which effects were checked elsewhere in the analysis.
Record waveform, frequency, load level, and winding or device temperature.
Documenting the calculation
Document voltage dropped and load current with regulator heat. Keep enough context to reproduce the result later.
Pass regulator heat unchanged when passing it to the next worksheet. Apply standard sizes only after all checks are complete.
Questions about Linear Regulator Heat
Should a blank measurement be entered as zero?
Leave the case unfinished until the real value is known rather than entering a placeholder zero.
Should I use measured or nameplate values?
Use voltage dropped and load current from one operating condition. Record waveform, frequency, load level, and winding or device temperature.
What is not captured by this equation?
The result follows the displayed variables. Check diode loss, ESR, regulation, ripple current, and thermal resistance separately.
Why might measured regulator heat differ?
First confirm that the measurements match the equation. Then review isolation, creepage, waveform shape, and manufacturer operating limits.
What should remain fixed in an alternate case?
Change one uncertain entry at a time and preserve the baseline. Identify RMS, average, peak, and rectified quantities explicitly.