FORMlxSWRTHYPHASCISPELPRGHDOC h PICP69LINP6Z BOXP6Z dOVLP6Z dSWCL@BlackWhiteRedGreenBlueCyanYellowMagentafSalmonwPeachUBrownellowLight GreenwwwGrey DarkOrangeݙVanillalowGrey LightIDXHIDXDSoftSansdTitleepz,IDXDSoftSansdBlank LinefIDXDSoftSansdLetter HeadergIDXDSoftSans dIndex EntryhTOCH TOCDSoftSansdTitlenz%TOCDSoftSans dBlank LineoTOCDSoftSansdZLevel 1pTOCDSoftSans dZLevel 2qTOCDSoftSerif dLevel 3rTOCDSoftSerif dhLevel 4sTOCDSoftSerif dvLevel 5tTOCDSoftSerif d*Level 6uTOCDSoftSerif dLevel 7vTOCDSoftSerif d8Level 8wIDXPSEC1 PTPAG3pA PRN3KBVtils:APPLICATIONS/FinalWriter/FWFonts/SWOLFonts/Serif/WŬWW~WW { dELX.FormulaText{WPASDSoftSansdDocument TitlePASDSoftSansdSection Namepz??PASDSoftSansdTopic Nameq{??PASDSoftSansdSub Topic 1r|??PASDSoftSansdSub Topic 2s}??PASDSoftSans dBodyPASDSoftSans dIndented BodyTOCP!rOUTPBIBPTOIPENDPDSP2PHHFDASoftSans dSoftSans dPNDASoftSans dSHPP6Z dGRMRStrictly.For Business Writing.For Casual Writing.Custom 1.Custom 2.Custom 3.IDXLConductorsTDINFFCOP3` W=,W,FDTASoftSans_Bold{WŬWΆWvtUtils:APPLICATIONS/FinalWriter/FWFonts/SWOLFonts/xg6cl3`00000000?0@0@0>0@0"0@0A0@0@0  ?0@@@0@@  0@ 0   0@   0   0@  " 0@@  0@  B 0   0@ 1   0@ 2@  0@   4  ? @@?    0@ 0@@    0@ @0` 0  0@  @0P 0  0@ @@0@ @@  0@  0 D @P  0@  0@B @P  0@   0    0@ @@0@    0@ 0@ @  0@ 0 0`  0@ 0@    0@0P@   0@0   0@0@0 0@00  @@$I(@ @I$@@I$I$@ $I$I$I$@@@@:NF@BPI9@BPOt9 A$t@AH A$ A<8N A<A A ;p;pGINF SHD1PW2ZW2{W2xPTMainTBDYRULEOATTR dCHRSElectronic Servicing yr.1 pt.1ATTR dCHRS ATTR hdCHRS ATTR hdCHRS ATTR dCHRSLecture: 024 - tATTR [dCHRS ATTR hdCHRS ATTR hdCHRS ATTR hdCHRS ATTR hdCHRS Thursday - 10ATTR hdCHRS - AprATTR hdCHRS ATTR hdCHRS-1997RULEATTR hdCHRSRULE ATTR hxCHRS OscillatorsRULEATTR hdCHRSRULEATTR hdCHRSOscillators are used to generate alternating waveforms of varies types according to their shapes. Eg: Sine wave, sawtooth, triangular and square waves. The oscillator requires a dc power supply to operate, and since its output is ac, the oscillator can be regarded as a type of converter which transforms dc to ac. The frequency of oscillators can be varied by controls, but its amplitude is always constant.RULEATTR hdCHRSRULE ATTRhdCHRSSine Wave OscillatorRULEATTR hdCHRSThis produces a sinusoidal waveform (fig 4.7) which its frequency may lie between 5Hz to 20,000 Mhz. The output may be of a single frequency, sometimes preset to a number of different frequencies or variable over a band of frequencies. Some good oscillators have controls to adjust the frequency desired or select over the required frequency range. However the amplitude of the output waveform is always constant and is called continuous wave (c.w.)RULEATTR hdCHRSRULEATTR hdCHRSSine wave oscillators are used in master oscillators in signal generators, computer based systems, and transmitters and local or reference oscillators in receivers.RULEATTR hdCHRSRULE #ATTR#hdCHRS#Rectangular Wave (Pulse) OscillatorRULE,ATTR, hdCHRS,This oscillator produces a rectangular type of waveform (fig 4.8. It can either produces pulses with a short duration positive voltage and no negative voltage. Negative pulses can also be produced, where the pulses have a negative but no positive voltage. The rate of pulses is called the pulse repetition rate and could be any frequency from 5Hz to 1MHz. The width of the pulse (or mark) and the interval between the pulses (or space) can be made almost any desirable ratio, hence the mark-to-space ratio is adjustable for many good pulse oscillators. If the mark-to-space ratio is 1:1, then this means that the space and mark are equal, and hence a square wave is generated. (Fig 4.9). Application of pulse oscillators are found in general timing circuits, pulse modulators, colour TV receivers and computers.RULEATTR hdCHRSRULE ATTRhdCHRSSawtooth (Ramp) oscillator.RULEnATTR hdCHRSThis produces a waveform similar to a saw tooth as shown in fig 4.10. The sawtooth consists of two parts, hence the first which is the ascending part called the ATTR dCHRSscanATTRD dCHRSD which usually rises slowly, followed by the second part called the ATTR dCHRSflyback,ATTR+ dCHRS+ which is descending back to zero rapidly (at a greater steep from the scan). The frequency of these oscillators ranges from 0.083Hz (5 per minute) to 1MHz (1,000,000 per second). Sawtooth oscillators are commonly used for timebase applications in television receivers and cathode ray oscilloscope.RULEATTR dCHRSRULE ATTRdCHRSTriangular Wave OscillatorRULEATTR dCHRSThis is similar to the sawtooth but its rising and falling sections (hence the scan and flyback) have equal intervals, and hence the shape produced is that of an isosceles triangle (fig 4.11). The frequency is similar to the sawtooth oscillator, hence from 5 per minute to 1 million per second. One specialized use is in the production of pulse width modulated pulses and is found in some TV receivers.RULEATTR dCHRSRMSTRULEATTR dCHRSLMSTRULEATTR dCHRS