The project pertains to a standalone LED test tool that can be used to avoid the hassle of complicated LED testing using LED’s datasheet, multimeter, or power supply.
Explanation
There are several factors involved when selecting an LED for a project since various shapes and colors of LED electronic components are available in the market. The actual color of the LED, current required for the desired brightness, resistor size needed to achieve the current/brightness, and choosing the anode or cathode on the LED. Since the voltage drop of the LED varies based on current, computing the resistor value is not that easy.
As a power source, a 9V battery is used by the LED tester since it does not monopolize the bench variable power supply while providing portability. A double-sided sticky tape is used to attach the 9V battery to the PCB. The battery will last for many years so scraping off the tape when it is time to replace the battery will not be a problem because the circuit only uses between 2mA and 26mA when briefly lighting an LED and does not consume any measurable power when idle.
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