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 ...

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 ...

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 ...

Early last spring, we featured a book review, as part of our occasional Books You Should Read series. Usually these are seminal tomes, those really useful books that stay with you for life and become ...