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 ...

The circuit below illustrates powering a LED (or two) from the 120 volt AC line using a capacitor to drop the voltage and a small resistor to limit the inrush current. Since the capacitor must pass ...

Unlike filament lamps, where electrical energy must be converted into heat before light can be produced, Light Emitting Diodes (LEDs) are able to transform electrical energy directly into light energy ...