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 ...

[Kevin Darrah] wanted to make a simple 3.3V regulator without using an integrated circuit. He wound up using two common NPN transistors and 4 1K resistors. The circuit isn’t going to beat out a cheap ...

Solid-state device technologies, which are available to the amplifier designer, fall, broadly, into three categories: bipolar junction transistors (BJTs) and junction diodes; junction field effect ...

Over the recent weeks here at Hackaday, we’ve been taking a look at the humble transistor. In a series whose impetus came from a friend musing upon his students arriving with highly developed ...

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 ...

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 ...

A transistor is a key component in electronics, often used as a switch or to amplify a signal from a sensor. NPN (negative-positive-negative) transistors are the most used transistor. An illustration ...