Q1. Discuss in detail isolation amplifier in detail with diagram?
Isolation amplifier as the name propose is a type of differential enhancer that gives electrical disconnection and an electrical security hindrance for estimating signals with little recurrence in the presence of a high basic mode voltage.
They “re basically instrumental in viable protecting purposes as they shield information obtaining parts from basic mode voltages ,which are potential contrasts between the instrument and flag grounds. In situation where regular mode voltage associates with instruments without separation intensifier ,for the most part a loud portrayal of the flag under scrutiny is the last item , this is a direct result of no confinements on the dissemination of ground streams .if there should be an occurrence of sufficient level of mode voltage for the reason ,instrument annihilation is likewise a probable pay.
Segregation speaker additionally discover execution in pharmaceutical hardware (e.g life bolster) to guarantee disengagement of a patient from the spillage current by means of intensity supply.
These are additionally utilized in protecting the enhancer and instrument as an aggregate unit without rescuing precision of estimation as it permits the front end of the intensifier to coast concerning basic mode voltage ,moving toward the disengagement boundary ‘s breakdown voltage lying in the overabundance of 1000 volts now and again.
These speakers are likewise utilized for opening up different low level flags in fluctuated numerous channel applications .Measurement blunders because of ground circles can likewise be sidestepped .Moreover ,enhancers with inward transformers dispense with outer disengaged control supply, subsequently adequately changing the electric regularities to the client and instrument ‘s support. They are typically utilized as simple interface between Frameworks with isolated grounds.
Detachment intensifiers cam likewise incorporate confined power supplies for both info yield stages ,or outside power supplies on each disconnected bits for the above use.
Q2. Why do we need a saw tooth voltage to display a waveform on a CRO . Explain how Lissajous patterns are used in a CRO to measure an unknown frequency.
The time base generator which is responsible for producing the sweep and that will be amplified by the horizontal amplifier and then carried to the deflection plates of a CRO.
Sawtooth voltage play an important role to deflect the beam along X- axis and to refresh the CRO screen after every cycle giving stable image. Without sweep voltage the image displayed in screen will be a straight line.
CRO plays an important role in analysing the wave form of different signals. The main part of the CRO is CRT consist of
(vertical deflection plate, horizontal deflection plate ,electron beam).
When two different sine waves simultaneously applied to horizontal and vertical plates the pattern which is obtained in CRO screen is called Lissajous pattern. If the shape of Lissajous pattern has slight change then it also reflects into the phase difference and also in the ratio of frequencies of two sine waves .
Q.3 A DMM has 4 ½ digit display .What is the maximum number it can read ? What is the resolution ?
If the DMM has 4 ½ digit display then it means that there will be five segments , one half digit and 4 half digits. The maximum number it can read would be 19999.
If we want to display 10 KV on a 4 ½ digital display we will use the leading half digit and in this case we will have five digit of resolution.