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Single Phase Induction Type Energy Meter Single phase induction type energy meters are extensively used for the measurement of electrical energy in single phase A.C circuits. One can find such meters installed in homes. It is also called as single phase watt-hour meter. Single Phase Induction Type Energy Meter Principle: torque is produced to rotate the disc is due to interaction of two fluxes. Since the e.m.f induced in the disc by induction, this instrument operates on A.C only. Construction: The below fig shows the various parts of a single phase induction type energy meter. It consists of a shunt magnet, a series magnet, a rotating disc, a brake magnet and a counting mechanism. The shunt magnet consist of a number of M shaped iron laminated core wound with a fine wire of many turns i.e. coils and is connected across the supply. The shunt coil carries a current proportional to supply voltage and is known as Pressure coil . The flux produced by shunt magnet lags behind the supply v...

Output form Transistor Amplifier The below fig shows the common emitter transistor amplifier. There are two ways of taking output from the transistor amplifier. The output can be taken either across R C or across terminals 1 and 2. In either case the magnitude of output is the same. Suppose if we take the output across load resistor R C in the collector circuit i.e. Output = Voltage across R C = I C R C      …………………… (4) This method of taking output from collector load is used only in single stage amplifiers. The output can also be taken across terminals 1 and 2 V CE = V CC – I C R C            …………………. (5) From this V CC is a D.C. Voltage and cannot pass through capacitor C C therefore only varying voltage I C R C will appear across terminals 1 and 2.  Output = I C R C From expression (4) and (5) it is clear that the magnitude of output is the same whether takes output across collector load or ...

I’ve already shown how to drive an N-channel MOSFET (or even an IGBT) in both high-side and low-side configurations in a multitude of ways. I’ve also explained the principles of driving the MOSFETs in these configurations. The dedicated drivers I’ve shown so far are the TC427 and IR2110. Some people have requested me to write up on MOSFET drive using the very popular TLP250. And I’ll explain that here. The TLP250, like any driver, has an input stage, an output stage and a power supply connection. What’s special about the TLP250 is that the TLP250 is an optically isolated driver, meaning that the input and output are “optically isolated”. The isolation is optical – the input stage is an LED and the receiving output stage is light sensitive (think “photodetector”). Before delving any further, let’s look at the pin configuration and the truth table. Fig. 1 - TLP250 Pin Configuration Fig. 2 - TLP250 Truth Table Fig. 1 clearly shows the input LED side and the receiving photodetector as well...

Block diagram of CRO The below fig gives the block diagram of a CRO. A CRO consists of the following main blocks. 1.        Cathode Ray Tube (CRT) 2.        Vertical amplifier 3.        Delay line 4.        Trigger circuit 5.        Time-base generator 6.        Horizontal amplifier 7.        High / low voltage supply. Pic 1 Block Diagram of CRO CRT is the heart of the CRO. It produces visual pattern on its screen. An electron gun assembly produces a sharp beam of electrons which is accelerated and made to strike fluorescent screen. On the other side of this screen, a small visual spot is produced. In this journey from the electron gum, the electron beam passes through a pair of vertical deflecting plates and another pair of horizontal deflecting plates. The vertical deflecting pl...

Block diagram of AM transmitter and receiver with explanation AM Transmitter : Transmitters that transmit AM signals are known as AM transmitters. These transmitters are used in medium wave (MW) and short wave (SW) frequency bands for AM broadcast. The MW band has frequencies between 550 KHz and 1650 KHz, and the SW band has frequencies ranging from 3 MHz to 30 MHz. The two types of AM transmitters that are used based on their transmitting powers are: ·          High Level ·          Low Level High level transmitters use high level modulation, and low level transmitters use low level modulation. The choice between the two modulation schemes depends on the transmitting power of the AM transmitter. In broadcast transmitters, where the transmitting power may be of the order of kilowatts, high level modulation is employed. In low power transmitters, where only a few watts of transmitting power are required , low...

Power Factor Meter The power factor of an A.C circuit can be calculated from the following relation by measuring the current, voltage and power. I.e. cosΦ = P/VI. This method of determining the power factor of an electrical A.C circuit, is however, of low accuracy has a number of draw backs. Hence, it is desirable to have an instantaneous indication of the power factor of an A.C circuit, especially where it is varying continuously. Therefore, a power factor meter is connected in the A.C circuit to measure power factor which indicate directly by a single reading. There are two types of power factor meters: 1.        Electrodynamometer type of p.f meters                (a)      Single phase                 (b)      Three phase 2.        Moving iron type p.f meters             ...