[Eric Wasatonic] had a box of SWB2433 transistors that he had very little information about. In order to discover their properties, he fired up his curve tracer to compare these transistors with more ...

The ubiquitous LED continues to expand frontiers and applications with a plethora of sizes, colors, and output lumens. Flashing LEDs that incorporate internal electronics for oscillation offer ...

A previous Design Idea describes a circuit that uses an astable multivibrator to drive an LED (Reference 1). The circuit in Figure 1 uses a simpler alternative approach. The circuit uses a 2N3904 NPN ...

Frank Hertel’s project: three individually dimmable LED lights. (Frank is the master of recycling; the wooden mounting pedestals are the panels from a decommissioned ATI console!) Thanks for your ...

1. Bob Pease used an LM334 current source to servo the current from a PNP transistor through an LED diode. The LM334 will draw current into its V+ pin until the voltage on the R pin reaches 0.068 V.

With cycling safety in mind, I bought a pair of low power red LED things that replace the bungs in the end of drop handlebars. They are a neat way to get a bit of extra visibility – and to give a ...

– 6 super-bright white LEDs (Ours were rated for 3.3v with an intensity of 7000mcd.) – 1 2N2907 PNP Transistor (We found ours in a 15 transistor combo pack from RadioShack.) – RadioShack 3x2x1″ ...