Circuit works:
1. Frequency Modulation (FM) section:
CD9088 is a dedicated single-chip FM radio chip,
Its simple external circuit, the circuit was built frequently 70KHZ phase locked loop system, selectively implemented by active RC filter, mute circuit can be suppressed non-IF signal and the IF signal is too weak.
FM signal input circuit rod antenna C8 / C10 and L1 IC1 11, 12 feet into the mixer circuit, local oscillation circuit uses a variable capacitor CA / L2, etc. vitality can be achieved manually tune.
Circuit R2 / C2 to squelch circuit, 3 feet to the audio loop filter capacitor C4.
Indirect C13 6,8 feet of the intermediate frequency feedback capacitor, 7 feet is connected to C14 was the low-pass capacitors,
between C17 of 8/9 feet is IF coupling capacitor , 10 feet connected to the C12 is a limiting amplifier low-pass capacitors, 13 feet connected to the C6 of the limiter offset voltage capacitors.
2. Amplitude modulation (AM) section:
AM band using Direct IC TA7642, TA7642 IC has 10 transistors internal composition, its appearance uses encapsulation mode a TO-92,1 feet grounded, 2 feet input , 3 feet output. Audio signal output from 3 feet, through R6 / C18 is coupled to the input of the power amplifier IC TDA2822 the power amplifier, pushing the speaker working.
Package included:
1PC AM FM Radio Kit Parts CF210SP Suite For Ham Electronic Lover Assemble DIY NEW
Note:
The product needs to be assembled
Please allow 0.5-1cm differences due to manual measurement.
Due to the light and screen difference, the item's color may be slightly different from the pictures.