Electronic USB discharge load with switch-selectable parallel resistors — ideal for controlled USB load testing and capacity/discharge checks. Key benefits Simple selectable loads: switch between discrete resistances or combine them in parallel to produce three distinct load modes for versatile testing. Accurate, repeatable discharge: use the included resistor options to create reliable, measurable loads for USB ports, power banks, and chargers. High-power handling per resistor: each resistor is rated at 10 W, enabling sustained discharge tests without immediate overheating. What it does (function and standout features) Selectable resistors arranged in a parallel topology and controlled by switches allow three effective resistance options: 2.2 Ω (10 W), 4.7 Ω (10 W), or both resistors used in parallel. When both resistors are engaged in parallel the device produces a lower combined resistance and higher discharge current; at 5 V this combined mode can produce nearly 3 A of discharge current. Switch-based selection gives fast, tool-free changes between load modes for bench testing and field use. Compatibility and performance Designed for USB/5 V systems. Use the device to apply a controlled resistive load to USB power sources, power banks, chargers, or USB ports. Resistances and power ratings: 2.2 Ω at 10 W 4.7 Ω at 10 W Both resistors in parallel (switch selectable) for the combined low-resistance mode Use Ohm’s law to calculate actual current: I = V / R Use the parallel resistance formula for multiple resistors: R = 1 / (1/R1 + 1/R2 + ... + 1/Rn) Practical examples / use scenarios Power bank capacity and discharge testing: apply a stable resistive load to measure how long a power bank sustains output at a chosen current. USB charger and port verification: check voltage stability and thermal performance under known loads by switching between the available resistances. Device troubleshooting and development: reproduce expected load conditions for firmware, battery management, or charging-circuit validation. How to use (brief) Connect the load to the USB 5 V output under test. Select the desired resistor mode with the switches: 2.2 Ω, 4.7 Ω, or both in parallel. Calculate expected current with I = V / R and verify it stays within the resistor power ratings (each resistor is 10 W). Monitor voltage and temperature during extended tests. Notes and practical considerations Each resistor is rated 10 W; ensure the power dissipated (P = V * I = I^2 * R) stays within rating for extended tests or use intermittent testing to avoid overheating. The device provides clearly defined resistance options; use the formulas above to compute exact resistance and current for your test conditions. Specifications summary Selectable resistor values: 2.2 Ω (10 W), 4.7 Ω (10 W), or both in parallel Intended supply voltage: 5 V USB Selection method: manual switches Key equations provided: parallel resistance R = 1/(1/R1 + 1/R2 + ... + 1/Rn) and Ohm’s law I = V / R This device delivers a compact, switch-selectable resistive load solution for USB discharge and testing needs, with clear resistance options and straightforward calculations for predictable, repeatable results.