Electrical4U 
An electronic DC voltmeter measures direct current (DC) voltage between two points in an electric circuit. Connect it in parallel with the points under test and observe terminal polarity. Electronic instruments use input protection, range networks, buffers, amplifiers and analogue-to-digital converters. Components such as diodes protect or condition the input; transistors and amplifiers provide high … Read more
A capacitor stores separated electric charge and energy in an electric field. Capacitors support power conversion, motor starting, filtering, timing, signal coupling and many other functions. Their voltage, capacitance, polarity, dielectric, temperature and ripple-current ratings vary widely. The same stored energy that makes a capacitor useful can remain hazardous after power is removed. This guide … Read more
What is an Astable Multivibrator? An astable multivibrator is a free-running oscillator with no stable output state. After power is applied, feedback makes it alternate continuously between two temporary states without a recurring external trigger. Its output is usually a rectangular waveform rather than a perfect square wave. The other main multivibrator modes are the … Read more
What is a Thermocouple? A thermocouple uses two dissimilar conductors called thermoelements. A joint forms the measuring junction, while the other ends connect to an instrument. Temperature gradients along the two conductors produce a small electric voltage through the thermoelectric effect. Thermocouples cover many temperature and environment combinations, but performance depends on the type, wire, … Read more
A 7-segment display is defined as a device that shows numbers and some letters by lighting up various segments. Each segment is a light-emitting diode (LED) or a liquid crystal display (LCD) that can be turned on or off by applying a voltage. A 7-segment display has eight segments, including a decimal point (DP), arranged … Read more
What is Thermionic Emission? Thermionic emission is the escape of electrons from a heated surface. Thermal excitation places a fraction of the electrons above the surface energy barrier. The work function is the energy difference relevant to removing an electron from the material’s Fermi level to vacuum just outside the surface. Thermal electron emission was … Read more
An operational amplifier, or op amp, is a DC-coupled amplifier with two input terminals and one output. Its high differential voltage gain becomes useful when external feedback sets a controlled circuit response. Supporting resistors and capacitors let op amps amplify, add, subtract, integrate, differentiate, filter or generate signals in oscillators. The 741 is a long-established, … Read more
A digital multimeter (DMM) combines several electrical measurements in one instrument. Most models measure voltage, current and resistance. Selected models also measure capacitance, frequency or temperature and may include continuity and diode test modes. Each function has its own input limits, terminal arrangement and safety procedure. Read the exact meter manual before use, especially for … Read more
What is the Plum Pudding Model? The plum pudding model is a later name for J. J. Thomson’s 1904 model of atomic structure. Thomson placed negatively charged corpuscles, now called electrons, inside a sphere of uniform positive electrification. Equal positive and negative charge made the atoms electrically neutral. The British dessert analogy compares the diffuse positive sphere … Read more
A ring counter consists of flip-flops arranged in a sequence where the output of the last flip-flop loops back to the first, forming a circular structure. A counter is a digital device that counts the number of pulses or events that occur in a given time interval. A flip-flop is a bi-stable device that can … Read more