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 ...

A very simple but highly efficient combination lock circuit is shown in the figure. Any type of on/off switches can be used, varying from commercially available inexpensive types to more sophisticated ...

The Joule Thief Circuit is a simple and clever electronic design that can power an LED using a nearly dead battery. The project demonstrates how basic components like a transistor, a toroidal coil, ...

Looking at some anecdotal stories as well as some reasonably valid survey data, it seems that STEM-related subjects are getting serious interest from students at all age levels; STEM stands for ...

Ever wondered how a solar-powered lamp powers an LED with just a single 1.2 V cell? A closer look reveals a clever single-transistor voltage converter circuit. Curious how a solar-powered lamp powers ...

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 ...

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 . . .