ULV 100 resistor Datasheet: Critical Specs & Charts

28 May 2026 2

When specified correctly, a ULV 100 resistor’s continuous power, thermal impedance, and derating curve determine whether it survives a high‑energy braking event or fails in minutes. This guide extracts the critical datasheet specs and shows how to read the charts engineers need to select and integrate a ULV 100 resistor reliably. Readers will get a stepwise checklist, sample tables and worked thermal calculations to validate selection under steady and pulsed loads.

Background: What the ULV 100 resistor is and where it's used

ULV family parts are typically vertical metal‑clad or wirewound power resistors engineered for dynamic braking and load‑bank duties. Common mechanical forms include flanged or chassis‑mount cans with bolted terminals. Choose the form factor that matches your cooling strategy (free air, forced air, or heatsink contact) to ensure low thermal path resistance.

IN OUT VCC GND ULV 100 CORE

Key datasheet specs for ULV 100 resistor

ParameterExample ValueNotes
Resistance100 ΩFixed wirewound element
Tolerance±5%Standard; ±1% available for precision
TCR±150 ppm/°CDefines drift over operating temp
Rated Power100 W @ Tcase=25°CChassis-mount referenced
Max Voltage500 V DCCheck AC peak derating

Power ratings and derating curve

Continuous rating and derating determine allowable sustained loads. Apply the formula: P_allowed = P_rated × derating_factor(Temp). For example, if derating at 60°C is 0.7, a 100 W rated device is limited to 70 W. Annotate your datasheet curve to show your specific operating point and required safety margin.

Interpreting thermal & electrical charts

Zth(t) (Thermal Impedance) shows how the resistor converts energy into temperature rise for pulses. To estimate short‑pulse temperature rise, use ΔT = E × Zth(t). Worked example: A 500 J pulse with Zth(50 ms)=0.08 °C/J yields ΔT = 40 °C. If the baseline case is 40 °C, the peak reaching 80 °C must remain below the maximum allowable case temperature.

Example spec breakdown: Walkthrough

A short checklist prevents costly mismatches. Verify resistance, confirm continuous power at specified Tcase, check max voltage, and inspect Zth(t) curves. Red flags include missing derating data or undefined Tcase probe locations. Plan bench thermal tests that replicate worst‑case duty cycles in representative enclosures with planned airflow.

Summary & Quick Reference

  • Verify ratings: Confirm resistance, tolerance and voltage limits against system demands.
  • Calculate thermal margin: Use Zth(t) for pulses and derating curves for steady load to ensure >20% margin.
  • Perform bench tests: Replicate worst‑case braking pulses and steady state in the planned enclosure.
What is the best way to verify a ULV 100 resistor will survive a braking pulse?

Run a pulse test that reproduces the expected energy and repetition rate, measure case temperature at the datasheet‑specified point, and compare the measured ΔT to the predicted ΔT = E × Zth(t). Confirm cooling recovery between pulses matches system duty cycle.

How do I choose derating margin for continuous braking?

Start with the datasheet derating curve referenced to case or ambient, then apply a safety margin—commonly >20% for unknown duty cycles. Validate by measuring steady‑state temperature under intended continuous load in the final mounting arrangement.

When is a thermal impedance chart required versus a simple power rating?

Use Zth(t) when pulses, inrushes or short energy events dominate thermal stress. For steady continuous dissipation, the case‑referenced rated power and derating curve are sufficient. Combine both for complex duty cycles.

What are the critical electrical fields to check on a ULV 100 datasheet?

Focus on nominal resistance, tolerance (±1% or ±5%), TCR (ppm/°C), max continuous voltage, and the short-term overload (STOL) rating to ensure the component handles startup transients without degradation.