Download this article in PDF format. High-brightness visible-light LEDs (VLEDs) require a constant-current source. This simple, RFI-free circuit takes advantage of the normally-on properties of the ...

This Design Idea is a two-wire current regulator that strikes a good balance between performance and parts count. Employing three transistors, three resistors, and one LED, it achieves good regulation ...

Controlling LEDs is really quite simple. As you know, they need to be current limited which is as easy as applying Ohm’s law to your given set of values. To make things even more even there’s a slew ...

Nerd Ralph loves cheap and dirty hacks, and for that we applaud him. His latest endeavor is a LiFePO4 battery charger that he made out of parts he had on hand for under $0.50 US. (Although we think he ...

An idea in an earlier blog is to make a pwm interface that can accept 5, 12 and 24V pulse streams. That one uses a bunch of resistors and has three separate inputs. Below that, wise commenter DB ...

In designs using multiple LED strings such as brake lights, daytime running lights, rear lights and other automotive lighting applications, current-balancing circuits supply equal current to all LED ...

In this lesson, students build two circuits and explore how transistors function. When Bell Labs introduced the transistor in June of 1948, a spokesman proudly announced "This cylindrical object . . .

Transistors are tiny electronic components that act as switches and amplifiers, and they dwell at the heart of modern technology. In simple terms, a transistor can turn a flow of electricity on or off ...