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 ...

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 ...

Thermocouples and their leads often have to detect open-circuit or short-circuit faults. However, it is very difficult to distinguish a valid millivolt temperature signal from an open/short-circuited ...

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 . . .

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 ...

Reverse polarity is one of the most common causes of circuit failure, from hobby projects to industrial systems. The good news is that a well-designed reverse polarity protection using MOSFET ...

The circuitry we rely on today comes from what could be considered a top-down approach, with the wiring completely laid out before it’s etched into silicon. With the advent of nanotechnology, however, ...

If you cultivate an interest in building radios it’s likely that you’ll at some point make a simple receiver. Perhaps a regenerative receiver, or maybe a direct conversion design, it’ll take a couple ...