Bipolar Junction Transistor (BJT) Overview, Operating Modes, Switches, and Relay Driver Circuits Supplies Needed (if you’d like to build the following circuits) BJT Overview The BJT or bipolar junction transistor is a 3-terminal semiconductor device that can be used amplify current. The three terminals are the emitter, the base, and collector. The BJT is primarily used in three operating modes: […]
How to light an LED
Considerations when Lighting an LED There are two primary considerations for lighting an LED. LED Polarity LED current LED Polarity LEDs are diodes – and diodes only pass current in one direction. Therefore, if you hook an LED up backwards, it won’t light, and can even be damaged. Below is the schematic symbol for an LED. Note the direction of […]