The polarity markings on LEDs (Light Emitting Diodes) seem to be a common cause of confusion. The polarity may be indicated by a flat section on one side of the body or by one lead being shorter than ...

This circuit can be used to test up to three LEDs at once, connected in series. You can easily increase that number by using a higher supply voltage. If you do so, you should allow 2.7 V for each ...

Instructables user [Rudolf] wrote in to share a handy little tool he created with ham radio operators in mind. Now and again, he found himself connecting to an unknown power supply, and rather than ...

Here are two simple tools for the Hobbyists to check their Prototype boards. These use LEDs as visual indicators for the quick check reducing the job of multimeter testing This can be used to check ...

The CT20 is a two-part system consisting of a master continuity tester/transmitter and a two lead, bi-color (red/green) LED remote probe. The continuity tester/transmitter is used for local continuity ...

If you’ve worked on a project with small LEDs, you know the frustration of determining their polarity. This ingenious LED Probe from [David] packs a lot of useful features into a simple, ...