One of the questions that hobbyists ask over and over is how to select the value of a current limiting resistor for an LED. Usually the seat of the pants response is: “Subtract 2 V from the supply ...

A solar day lamp is a simple, inexpensive device for bringing “daylight” to dark interior spaces whenever the sun is shining. This article provides complete instructions for designing lamps using both ...

Light-emitting diodes (LEDs) are often used with a voltage source from a power-supply output voltage. The output voltage increases until the current through the LEDs reaches the value of the ...

Lighting a string of LEDs at a constant brightness requires driving it with a regulated current. A boost converter is commonly used to step up the voltage to a level high enough to bias the LEDs on ...

If you got your start in electronics sometime after 1980 your first project might well have been to light up an LED. Microcontroller projects often light up an LED, too, and a blinking LED is ...

Linear constantcurrent drivers, for instance, offer low EMI, low cost, and use only a few components. Many designers favor them for low-current applications where power loss is a minor concern. If ...

How to build a photovoltaic light system that operates at all times and is maintenance-free. The key role of the supercapacitor in this design. What is the "Joule Thief" circuit? Delivering ...

• The inductance in a stepper-motor phase winding limits how fast current rises when power is applied. • Series-resistor current limiting needs higher voltages for faster step rates, but higher ...