It has been seen that intense corona effects are observed at a working voltage of 33 KV or above. Therefore, careful design should be made to avoid corona on the sub-stations or bus-bars rated for 33 KV and higher voltages otherwise highly ionized air may cause flash-over in the insulators
Year: 2014
For high voltages (>33 KV), it is a usual practice to use suspension type insulators consist of a number of porcelain discs connected in series by metal links in the form of a string. The conductor is suspended at the bottom end of this string while the other end of
Lissajous figures (or patterns) are named in honor of the French scientist who first obtained them geometrically and optically. They illustrate one of the earliest uses to which the CRO was put. Lissajous patterns are formed when two sine waves are applied simultaneously to the vertical and horizontal deflecting plates
No other instrument in electronic industry is as versatile as a CRO. In fact, a modern oscilloscope is the most useful single piece of electronic equipment that not only removes guess work from technical troubleshooting but makes it possible to determine the trouble quickly. Some of its uses are as
It is the heart of an oscilloscope and is very similar to the picture tube in a television set. CONSTRUCTION The cross-sectional view of a general purpose electrostatic deflection CRT is shown in below Figure. Its four major components are: 1. An electron gun for producing a stream of electrons,
It is generally referred to as oscilloscope or scope and is the basic tool of an electronic engineer and technician as voltmeter; ammeter and watt meter are those of an electrical engineer or electrician. The CRO provides a two-dimensional visual display of the signal wave shape on a screen thereby
The schematic diagram of a FET Volt Meter using difference amplifier is shown in Figure. The two FETs are identical so that increase in the current of one FET is offset by corresponding decrease in the source current of the other. The two FETs form the lower arms of the
As shown Figure, an electronic instrument is made up of the following three elements: TRANSDUCER It is the first sensing element and is required only when measuring a non-electrical quantity, say, temperature or pressure. Its function is to convert the non-electrical physical quantity into an electrical signal. Of course, a
Both electrical and electronic instruments measure electrical quantities like voltage and current etc. Purely electrical instruments do not have any built-in amplifying device to increase the amplitude of the quantity being measured. The common dc voltmeter based on moving-coil meter movement is clearly an electrical instrument. The electronic instruments always
When a complex voltage is applied across a circuit containing both inductance and capacitance, it may happen that the circuit resonates at one of the harmonic frequencies of the applied voltage. This phenomenon is known as selective resonance. If it is a series circuit, then large currents would be produced
