Digital Electronics Articles - Page 52 of 57

Important TermsAC Circuit − A closed path followed by alternating current is called as an AC Circuit.Resistance − The measure of opposition offered by a material in the path of electric current is known as resistance of that material. The element possessing the resistance is known as Resistor.Peak Value of Voltage or Current − It is the maximum value attained by an alternating quantity. It is also called as Amplitude.Average Value − The arithmetical average of all values of an alternating quantity over one cycle is called as average value. For sinusoidal voltage or current, $$\mathrm{I_{avg}=\frac{2I_{m}}{\pi}=0.637I_{m}}$$$$\mathrm{V_{avg}=\frac{2V_{m}}{\pi}=0.637I_{m}}$$Root Mean Square (RMS) value ... Read More

When a p–type semiconductor is suitably joined to n–type semiconductor, the contact surface of the semiconductors is called as pn–junction.Properties of pn – junctionThe p–type semiconductor has holes and the n–type semiconductor has free electrons as the majority charge carriers. When both p–type and n-type materials are suitably joined together to form pn–junction. At the junction, the free electrons from the n–side diffuse over to the p–side and the holes from the p–side to the n–side. Since both the materials are electrically neutral, so a positive charge is build up on the n–side of the junction and negative charge on ... Read More

A practical operational amplifier exhibits some limitations that should be considered in the design of instrument.The Physical Limitations of Operational Amplifier −Voltage Supply LimitationsFinite Bandwidth LimitationsInput Offset Voltage LimitationsInput Bias Current LimitationsOutput Offset Voltage LimitsSlew Rate LimitationShort Circuit Output LimitsLimited Common Mode Rejection RatioVoltage Supply LimitationsAn operational amplifier is power by an external DC power supply (+VCC and -VCC), which are symmetric and of the order of ± 10 V to ± 20 V. The effect of voltage supply limits is that amplifiers are able to amplify the signals only within the range of their power supply voltage. It is ... Read More

The operational amplifier (also known as Op-Amp) is a multi-terminal direct coupled high gain amplifier which consisting of one or more differential amplifiers and a level transistor and an output.The Op-Amp is a versatile device which can be used to amplify both DC and AC signals and these are mainly designed for performing mathematical operations like addition, subtraction, multiplication etc.Block Diagram of Operational AmplifierInput Stage − The input stage is the dual input, balanced output differential amplifier. This stage provides most of the voltage gain and introduces the input resistance of operational amplifier.Intermediate Stage − This stage is dual input, ... Read More

A Metal Oxide Semiconductor Field Effect Transistor (MOSFET) has four terminals − Source (S), Gate (G), Drain (D), Body (B). It is a semiconductor device which is used for switching and amplification applications in electronic circuits. In general, the body terminal is connected with the source thus forming a three terminal device just like an FET.The MOSFET is a voltage controlled device. Since its operation depends upon the flow of majority carriers only, hence MOSFET is a unipolar device.In other words, An FET that can be operated in the enhancement mode is known as MOSFET.Why the Name MOSFET? The gate ... Read More

An operational amplifier is a three-terminal device consisting of two high impedance input terminals, one is called the inverting input denoted by a negative sign and the other is the non-inverting input denoted with a positive sign. The third terminal is the output of the Op-Amp.Inverting Operational AmplifierIn the inverting operational amplifier circuit, the signal is applied at the inverting input and the non-inverting input is connected to the ground. In this type of amplifier, the output is 180⁰ out of phase to the input, i.e. when positive signal is applied to circuit, the output of the circuit will be ... Read More

The Insulated Gate Bipolar Transistor (IGBT) is a semiconductor device having three terminals – Gate (G), Emitter (E), and Collector (C). IGBT has been developed by combining the best qualities of both BJT and Power MOSFET. Hence, an IGBT exhibits high input impedance as a PMOSFET and has low ON-state power losses like a BJT.The IGBT is also free from the second breakdown problem that present in the BJT.IGBT is also known as Insulated Gate Transistor (IGT), Metal Oxide Insulated Gate Transistor (MOSIGT), Conductively Modulated Field Effect Transistor (COMFET) or Gain Modulated FET (GEMFET).Basic Structure and Schematic Symbol of IGBTThe ... Read More

Basically a transistor is nothing but two pn-junctions connected back to back. By examining both the junctions (Emitter-Base junction and Collector-Base junction) with the help of a digital multimeter, we can comment on the functionality of the transistor.The test of the transistor is based on the principle of pn-junction biasing, i.e., when a forward bias is applied to the pn-junction (by connecting positive terminal to the p-region and negative terminal to the n-region), the junction allows current to through it. When the reverse bias applied to the junction, it behaves as an open circuit.NPN Transistors are widely used. We can ... Read More

Full Wave Rectifier is a diode circuit which is used to transform the complete cycle of Alternating Voltage (AC Supply) to Direct Voltage (DC Supply).In full wave rectification, current flows through the load in the same direction for the complete cycle of input AC Supply.Types of Full Wave RectifiersCentre Tap Full Wave RectifierFull Wave Bridge RectifierCentre Tap Full Wave RectifierThe circuit of centre tap full wave rectifier consists of following main components −Two DiodesA centre-tapped transformerA load resistanceWorking of Centre – Tap FWR CircuitPositive Half CycleDuring the positive half cycle of input AC voltage, the end A of secondary winding ... Read More

The Enhancement Mode Metal Oxide Semiconductor Field Effect Transistor (EMOSFET) is a three-terminal Device viz. Source (S), Gate (G) and Drain (D). The EMOSFET is a voltage controlled device.The EMOSFET can be operated in the enhancement mode only. The EMOSFET has no physical channel from source to drain since the substrate extends completely to the SiO2 layer.By the application of gate–source voltage (VGS) of proper magnitude and polarity the device can be made operating. The use of VGS induces an n-channel just below the gate terminal and this made the device operating.The minimum value of VGS of proper polarity that ... Read More