555 TV square grid generator circuit

Published:2011/6/15 3:58:00 Author:TaoXi | Keyword: 555, TV, square grid, generator circuit | From:SeekIC

As the figure 14-20 shows, the square grid generator is composed of the line frequency oscillator, the field frequency oscillator and the high frequency oscillator, it can be used in the overhaul and calibration of the TVs. The astable multivibrator is composed of the IC1(555) and R1, RP1, R3, C1, the f1=1.44/(R1+RP1+2R3)C1, by adjusting RP1, we can make the oscillation frequency on the 125kHz which is 8 times of the line frequency; the multivibrator is composed of the IC2(555) and R6, RP2, R8, C4, the f2=1.44/(R6+RP2+2R8)C4, by adjusting RP2, we can make the oscillation frequency on the 300kHz which is 6 times of the line frequency. The 57.75MHz wave-carrier oscillator is composed of the VT1 and L1, C7, C8, C12, it is adjusted by the output pulses of IC1 and IC2, and it radiates by the L1, C7 oscillation loop.



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