TWO_IC_AM_RADIO

Published:2009/7/16 3:59:00 Author:Jessie | From:SeekIC

National LM1820 IC serves for RF, oscillator, mixer, and IF stages of AM superheterodyne radio while LM386 IC is audio amplifier driving loudspeaker. Double-tuned circuit at output of mixer provides selectivity. Total gain from base of input stage to diode detector is 95 dB. CA is 140 pF, CB is 60 pF, L1 has 110 and 5 turns for broadcast band, L2 has 98 and 12 turns for oscillator, T1 has 140 turns center tap and 2 turns, T2 has 142 turns and 7 turns, and T3 has 142 turns center tap and 71 turns. IF value is 455 kHz. L3 has 3 turns on ferrite bead. - Audio Handbook, National Semiconductor, Santa Clara, CA, 1977, p 3-4-3-8.



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