Category: 8. Miscellaneous Circuits

An LED or Light Emitting Diode, is a solid state optical pn-junction diode which emits light energy in the form of photons. The emission of photons from a 7-segment display occurs when the diode junction of each segment is forward biased by an external voltage allowing current to flow across its junction, and in Electronics…

Christmas is coming and its that time of the year again when the electronics student or hobbyists thoughts turn to making a Christmas circuit for their home and especially one that flashes a few lights. There are many circuits and kits on the market that can flash any number of lights periodically, randomly or sequentially…

The current-voltage, (I-V) Characteristics Curves define the operating characteristics of an electronic device. The I-V Characteristic Curves, which is short for Current-Voltage Characteristic Curves or simply I-V curves of an electrical device or component, are a set of graphical curves which are used to define its operation within an electrical circuit. As its name suggests, I-V characteristic curves show the…

The Wheatstone Bridge is the name given to a combination of four resistances connected to give a null center value. The Wheatstone Bridge diamond shaped circuit who’s concept was developed by Charles Wheatstone can be used to accurately measure unknown resistance values, or as a means of calibrating measuring instruments, voltmeters, ammeters, etc, by the use of…

The Voltage Multiplier is a type of diode rectifier circuit which can produce an output voltage many times greater than of the applied input voltage. In the tutorial about Rectifiers, we saw that the DC output voltage being controlled by the rectifier is at a value below that of the mains input voltage. The Voltage Multiplier, however, is a…

An Optocoupler, is an electronic components that interconnects two separate electrical circuits by means of a light sensitive optical interface. The Optocoupler is an electronic component which can be used in many different applications as an interface between low voltage digital or control circuits and large power electronic devices. We know from our tutorials about Transformers that they…

3-terminal linear fixed voltage regulators are a popular choice for creating either positive or negative voltages. Continuing on from our tutorial about converting an ATX PSU to a bench power supply, one very good addition to this is the LM317T positive voltage regulator which we can use to create a variable voltage power supply. The…

Is it possible to use an ATX power supply unit or PSU from an old PC as a bench top power supply to power 5V logic, but with some limitations. The standard computer power supply unit (PSU) turns the incoming 110V or 220VAC (alternating current) into various DC (direct current) output voltages suitable for powering…

There are many different ways to control the speed of DC motors but one very simple and easy way is to use Pulse Width Modulation. But before we start looking at the in’s and out’s of “Pulse Width Modulation” we need to understand a little more about how a DC motor works. Next to stepper…

Passive devices are the main building blocks of electronic circuits and without them these circuits would either not work at all or become unstable. So what are Passive Devices. Passive devices or components do not generate energy, but can store it or dissipate it. Passive devices are the main components used in electronics such as resistors,…